On a sinking ship struck down in the North Sea young sailor Jay Selby staggers on deck wondering why the boat is sinking so fast, despite the fact not a shot has been fired. As the rest of the crew realise there are no lifeboats Jay realises that whatever took them did not show on the radar.
The crew capsize and as Jay flounders about remembering his mum and his sister Keisha, something grabs hold of his leg, puncturing the base of his neck and stabbing his back at the same time. Despite floundering for safety it is no use; he is plunged into the depths of the water as the creatures of the water swirl around him.
Some time later Rose sits in her friend Keisha’s living room, as she explains that Jay’s ship has been pulled up the Thames in a million pieces, yet still his death is unconfirmed, even though she knows he is gone. She admits she hasn’t the details to contact her mother on and is yet to tell her as Rose looks over to the Doctor, who stands staring out of a window.
After she asks about him Rose explains to Keisha that she met the Doctor the time she disappeared for twelve months, and after she admits the rest of her friends had thought Mickey had killed her the Doctor goes on to ask what Jay did on the ship. Seeing that it doesn’t lighten things he decides to go and buy them some chips, leaving the two girls alone.
No sooner has he left, the ghost of Jay appears in the corner of the room, a scarred phantom. Shivering, he calls for them to come and help him, rescue him before the feast. Suddenly, water flows from his nose and mouth and he fades away, leaving a pool of water than soaks into nothing. Keisha gets hysterical; telling Rose that she must find him and help him. The Doctor returns with the chips and news that some of the customers in the nearby newsagents have collapsed into fits. After he has finished Keisha tells him what they have just seen…
The Doctor and Rose leave Keisha to rest and on their way out the Doctor admits he has no belief the thing they saw was a ghost. He decides that they need to find out more about the ship Jay was on; the ‘Ascendant’ and that they so go to Mickey’s house to check the Internet.
Once there they find that the giant ship was sunk in the North Sea and that the entire crew was lost. It was brought up the Thames in pieces to a place called Stanchion House. Rose wonders why the ship was taken up in pieces and Mickey theorises it may have been to send different parts to different departments.
Soon he and Rose are arguing about Keisha, Mickey spouting that Keisha is a bad influence and Rose defending her. Loosing his temper he reveals that the first time she went away in the TARDIS for a year, Keisha had her friends push things through his letterbox and try to beat a confession out of him in regards to what had happened.
The Doctor tries to calm them down before revealing from one of the report he has read that around twenty people have gone missing around the Thames area since the Ascendant was brought up river. He decides it is time to go and look at the ship for themselves in the TARDIS but when Rose and Mickey agree t come with him the human traveller tells him that they are taking the bus.
Some time after they have arrived at the river where all bridges leading to Stanchion House have been closed. They find another woman, called Anne, who has also seen one of the beckoning apparitions, this time of her lost son Peter who was also on the Ascendant, and is trying to get to the wreckage to find her son before the feast.
After stopping her from jumping into the river they are confronted by a troop of soldiers who collapse in a fit. The Doctor takes one of their passes and runs off to get to Stanchion House. After Anne goes into panic over Peter, once again seeing his ghost calling out to her, and an ill-feeling Mickey helps call of an ambulance as the soldiers calm down, and a pool of water where Peter stood appears from the ground, trickling off to join with the river.
The Doctor arrives at Stanchion House where he introduces himself as Sir John Smith, Scientific Advisor to the Admiralty. As the receptionists tell him of the pedestrians jumping into the river in order to reach the Ascendant. The Doctor looks at the staff list and tells them he is here to see Vida Swann, and is then taken to his office.
At the riverside Mickey has been sick from dehydration and as Rose decides to take Anne to rest at her mum’s house a man called Rear Admiral Crayshaw approaches and tells them an ambulance for the fallen soldiers will not be necessary. He tells them that he and his men will look after them; he is in charge of the operation regarding the Ascendant. He dismisses the stories if people diving into the Thames and then sends them on their way before making his way back to Stanchion House, where Rose realises the Doctor is still at large within.
The Doctor is led to Vida Swann’s office where he uses his stolen pass to get inside. He discovers she is a Liaison Officer for the European Office Of Oceanic Research And Development. And after she accidentally hits him in the head by opening a door he introduces himself again as John Smith. He asks to be directed to where the pieces of the Ascendant were brought up the river. Instead she reveals that when he entered her computer read his pass as Sergeant Jodie North, she knows it is stolen. He finally introduces himself as the Doctor and then darts to escape, Vida having admitted she has already activated the alarm. He runs out into the corridor but the windows are locked, the lifts are full and on their way up, and the stairs are alive with the sound of approaching soldiers, he’s trapped.
As Vida un-eagerly awaits the arrival of Crayshaw the Doctor hides in a cupboard then sneaks into the lift where he uses a series of hidden button leads him deep below ground. In the streets of the city Rose phones Jackie but there is no room at the flat for Anne because a man called Dennis is coming round. After Anne start asking to be taken back to the river Rose decides to take her to Keisha, she knows about seeing one of the ghosts.
Crayshaw enters Vida’s office and she tells him the intruder wanted to know about the Ascendant. She goes on to criticise the treatment of her and her fellow scientists, they are denied information and have been labelled as a security breech and she is not even allowed to board the ancient tug moored outside. Crayshaw upholds his own scientists are able to deal with the ship. He tells her that her affairs must be dealt with elsewhere then leaves.
The Doctor arrives in the underground lair where he is introduced to a scientist named Huntly. Posing as a scientific advisor he examines the remains of the Ascendant, which has been carved perfectly into chunks. He asks how this was done when the technology shouldn’t exist. Huntly tells him it was not done by the humans; this was how the ship was found at the bottom of the ocean.
After arriving at Keisha’s flat Rose sees that she has been preparing for Jay to return, cooking his favourite dinner and facing all furniture towards the spot where he appeared. After Mickey and Keisha argue over their past encounters Mickey goes to get more water to cure his illness and Keisha comforts Anne, they are ready for the next time the ghosts return.
As the Doctor ponders what might have carved up the ship in such a way Huntly explains the pieces were brought up the Thames and brought down to the Unloading bay, which is connected to the underside of an ancient tug out in the river. Suddenly and alarm sounds and soldiers arrive to take the Doctor as the Time Lord says goodbye to Huntly and flees towards the unloading bay. Running along through chambers and into a large room where the cargo is brought down he seals himself away from the soldiers and is puzzled by the presence of salt water when the water is from the river. He decides to find out if he can get out the way the cargo came in runs off into the darkness.
Crayshaw arrives in the underground chamber and Huntly tells him what the Doctor, alias John Smith, has said about the way the ship was carved using hydrogen anti-cellularisation. He admits he is open to these knew ideas and before he leaves Crayshaw tells him to stay behind after his shift to talk to him, as the soldiers struggle to open the door the Doctor locked with the Sonic Screwdriver.
The Doctor arrives in a large chamber with no ceiling, stretching up into the darkness.
As he sniffs the salt water he begins to ascend the large ladders of what he presumes is a cargo lift. As he goes he realises someone else has recently done the same and pondering who, he continues. He arrives at the platform on which the cargo is placed and then finds the inspection hatch covered in blood. He reaches to release it but then gunfire rings out.
As Rose, Mickey, Keisha and Anne sit in silence Rose remembers life on Earth growing up and how the Doctor has helped her to grow up. Or grow old. Mickey decides to go to the newsagents and Rose remembers how the Doctor said that when he went there when fetching chips earlier he said some customers had collapsed in fits, the same time that Jay appeared, and the same happened to the soldiers on the bridge when Anne saw her son. She decides to visit the newsagents and find out more, telling Mickey to stay behind with Keisha.
The Doctor dodges the gunfire, organised by Crayshaw and gets into the inspection hatch as the soldiers are ordered to spread out and find him. Suddenly a ghostly voice tells its mignons not to kill all the soldiers, some are still needed. The escaping one will be taken and bound to swell numbers at the feast. The Doctor ponders if they mean him or the one who came before him. He wonders what the other escapee might have been running from before setting off to get to the tug before the soldiers cut off his escape.
Sloshing through the water he finds a figure standing before him, the other escapee. It asks him to help in a London accent. He looks upon the disfigured face calling for help and realises it is Jay, Keisha’s brother. He tries to help but two figures rise from the convulsing water, each dressed in different period costumes. They take the screaming Jay and pull him below the water level and are washed away in an unseen current. The Doctor vows to return and proceeds to the hull of the tug, and there to the cabin where he can hear the sound of footsteps coming towards him.
In the newsagents Rose discovers the people who collapsed in fits were suffering from advanced dehydration. She remembers how the ghost of Jay had spewed water from his mouth when he arrived in Keisha’s flat. Suddenly the woman behind the counter collapses and goes into spasm and before her Jay’s ghost appears again, telling her to save him before the feast.
After Mickey remembers his one night stand with Keisha, something he never told Rose about, he panics as Keisha and Anne start to see their lost ones again calling to him. He sees nothing but rushes outside to see people begin sick in the streets. He returns to the flat to try and stop Anne and Keisha from leaving. Anne escapes and he is forced to stop Keisha by shutting her in the bathroom. As she struggles to get out Rose knocks on the door and Mickey tells her about Anne. She bids him farewell and runs to find the old woman. Running through the streets she reflects on what has happened and calls for a taxi.
On the deck of the tug Vida curses Crayshaw and then finds the Doctor. He explains about the dissection of the ship by alien technology and some alien intervention of the crew as he saw with Jay. She admits that she knows nothing of what is going on as the Doctor traps at the controls of the boat. Suddenly he decides that they must move on before the soldiers arrive and prepares to launch the boat as more gunfire rattles out, Crayshaw doesn’t want him to get away alive…
Rose gets the cab driver to stop at a police station but when she gets out a lone policeman called PC Fraser tells her due to staffing issues they are closed. After Rose explains about Anne he explains she may well be in the river. He tells her that many people have been seen jumping in, like there was a curse drawing them there. He explains that despite the fact they have all gone in not one person has been retrieved from the water, as if something was taking them. He tells her to try a station in Waterloo for finding Anne and as he goes off Rose returns to the impatient cab driver.
On the tug the gunfire continues from the soldiers as the Doctor starts up the boats engines. Unable to see because of the tarpaulin draped over the vessel he manages to get them moving, explaining to Vide that Crayshaw will kill them both and claim it was an accident. He decides to move out and remove the tarpaulin so that they can get to somewhere more public and thus be safer. Vida protests but it is too late because he has already gone.
In Keisha’s flat Mickey struggles to keep the bathroom door closed and looses his grip on the handle. Keisha runs out but stops dead when a message plays on her answer phone from her mother, who she has not heard in years. She calms down and begins to weep as Mickey moves off to make some tea.
Rose stops her taxi and gets out, thinking she has seen Anne. However the woman she runs up to in not Anne and instead she is drawn to the sounds of mass screaming. She runs and finds herself at the side of the river, where soldiers are trying to hold back crowds of people wanting to reach their lost relatives from the Ascendant. An old man joins her and talks of the cursed waters but she dismisses him, explaining it is the ghosts of the dead.
Suddenly the Doctor appears struggling to free the tarpaulin on the tug that towed the wreckage up river. As Rose looks on he calls and says he’s aiming to stop it by crashing it into something soft; the large restaurant barge in front of him. She runs onboard and everyone starts to clear out as the Doctor instructs Vida to throw the boat into a handbrake turn. Soon she is on the deck with him and Rose is on her way from the barge as the two boats collide, crashing the barge into the side of the river.
Rose gets to her feet and the Doctor and Vida scramble onto the barge. Rose creates a distraction to busy the approaching soldiers and soon the three of them are on the roadside. They approach the waiting taxi driver and the Doctor tells him to go to the HQ of the European Office of Oceanic Research and Development, Mickey and the others can meet them there.
Back at Stanchion House Huntly sits waiting for Crayshaw to arrive. After some time he does so and decides to show him something. He takes him along a corridor to a giant pool of water, lined by stationary bodies. Crayshaw admits that they are dead, but still full of life. As Huntly stutters he tells him they want him to join the feast. He falls into the water and something stabs him in the neck, as he slowly becomes lost to the water.
In the cab the Doctor explains about the base and seeing Jay, the victim of an alien vivisection. Rose admits that when she saw him in the newsagents she had the urge to go and find him, to rescue him. The Doctor congratulates her on fighting the feeling, the apparitions rely on the trust of loved ones to bring them forward, and Rose always had a crush on Jay. Vida begins to contact her boss Andrew Dolan but he has disappeared ever since he was last seen with Crayshaw. They soon arrive at the office and the Doctor produces a bag of water he took when in the transport tunnels. As he disappears into a laboratory Rose prepares to phone Mickey and tell him to come and meet them.
In the flat Mickey takes down the address and then wakes Keisha initially reluctant she decides to come with him and together they leave, as Anne’s mobile phone starts to ring. In the laboratory the Doctor is examining the sample of water and as Rose looks on Vida explains that her research deals with using chemical tracers to measure pollution in the water, some of which were onboard the Ascendant.
The Doctor explains to them about the carved up ship in the underground chamber and then theorises that perhaps the aliens who did it wanted to steal the tracers. He then gets Vida to admit that when the Ascendant sunk she and Andrew tested water from the North Sea and found inhuman elements and proteins in the samples. They also found out that the drainage pit below ground was extended two months ago, as if someone was building something. She prepares more equipment and samples for the Doctor as he wonders where Keisha is; he needs to see if any of the alien proteins found where the Ascendant sank are also inside her.
He explains that they are fighting something that has an affinity with water; it can harness it. Rose realises that the reason everyone collapsed when the apparitions appeared was because they were feeding off of the water inside the people they were talking to, causing them to dehydrate. The Doctor has a hunch that the minerals may be present in Keisha’s blood because she has seen one of the creatures in the form of Jay’s apparition, it may even be in Rose’s blood. As he continues his experiments Rose ponders how long they have to stop the creatures they are up against.
Some time later the Doctor is conducting tests on Keisha having taken blood from Rose and using Vida as a control. He asks Mickey to help Vida search the computers for all information held on the crew of the Ascendant to see if there is a link between them and the young human gets to work. As the Time Lord examines Keisha he sees that the alien proteins are burying themselves into her and as a natural defence she is becoming her mutated, just as an oyster forms a pearl to get rid of dirt, her eyes are forming protective layers. The damage in Rose is less advanced because of her lesser exposure.
He realises that the aliens are using the sensory information of those they capture to transmit as pheromones to those the captive recognises. They take over the brain and help them to unscramble the information and see the apparition. It feeds off of the water in nearby humans in order to transmit, which causes the dehydration. That is why Mickey, who has never met Jay, cannot see his apparition and nobody but Anne could see her son Peter on the bridge where the soldiers collapsed. Keisha scolds his scientific analysis and storms out as the Doctor explains to Rose it is the alien proteins scrambling her brain. Soon Rose is gone as well, as from the ceiling of the lab water is dripping, soon pouring down and filling the room.
Mickey and Vida find no link between the files for the crew of the Ascendant. As they idly bring up files they find one for Crayshaw and suddenly they are sprinting to tell the Doctor what they have seen, according to his file Crayshaw is nearly two hundred and fifty years old. The Time Lord meanwhile sits in the laboratory before realising the water from his beaker is gone. Suddenly water flies out of the sink and attacks him, trying to force its way into his mouth and down his throat.
Rose catches up with Keisha but she is angry with the Doctor for being so cold hearted. As a row develops she bitterly admits that in Rose’s absence she and Mickey had an affair. As Rose reels back Mickey and Vida arrive but Rose explodes at him. Suddenly a wave of water floods the corridor. Three apparitions, a Victorian woman, a pirate and a U-boat captain appear, standing with pearls for eyes, and carry Vida away on a wave of water. As the water flows away carrying Vida with it Rose runs after her, realising she is not just giving chase to the water creatures, but running away from Mickey and Keisha behind her.
Vida is carried away by the water down into the sewers, where she wonders if her workmate Andrew will be waiting, having succumbed to the same fate. Rose is soon on her tail but fails to catch sight of her. Struggling to forget about Mickey and Keisha she grabs onto the back of a nearby police van, hoping she will find herself wherever Vida might have been taken. The Doctor meanwhile manages to expel the attacking water and it escapes down the drain. Mickey and Keisha arrive and Mickey explains about their attack. He explains about Crayshaw and his age. The Time Lord explains he must have drowned at sea and the aliens got him, the salt water and the alien biochemistry being used to sustain him. He decides they must get to Stanchion House, where he proposes the water will have taken Vida, they will pick Rose up on the way.
The police van comes to a halt by the river and after finding no sign of Vida, Rose looks over the barrier where a bus has driven through into the dark waters. She sees PC Fraser, who explains his friend has been taken; he must get to him. He dives into the water and Rose screams but soon joins him when she looses her balance and falls in. She struggles to get out but something punctures her neck. As she begins to fall deeper into the murky depths she struggles to get free.
After finding no sign of Rose or Vida the Doctor, Mickey and Keisha return to the estate where Keisha admits it was her who tried to seduce Mickey, but when he crashed out at a party she waited until he woke and convinced him they had slept together. She lied to get back at Rose, her best friend who left her and never said why, who deserted her for life with the Doctor. They are interrupted by Anne’s abandoned phone and after checking her messages realises that she to has jumped into the river; and her family are looking for her.
Mickey begins to realise it is an unstoppable cycle. The crew of the Ascendant are drowned then call out to their loved ones. They then fall into the river, drown, and call out to their loved ones, and on it goes. He runs to tell the Doctor who is sitting outside but as he goes he is stopped by another apparition appearing in the room, calling for him and Keisha to come and save them before the feast. Only this is not Jay, it is Rose.
Vida awakens in one of the carved sections of the Ascendant and is confronted by Crayshaw, who speaks with a ghostly alien voice. Around her she sees the bodies of many people including Andrew Dolan and Rose. Crayshaw explains they are growing gills, to live under water with. He explains his race are of the waterhive, and they need Vice Admiral Kelper. He explains that Vida will be used to lure Kelper to them and then they will use him and his power to take over, after all the hour of the feast is approaching.
Elsewhere the Doctor admits he to saw a ghost of Rose but it is no time to panic. He yells at the frantic Keisha and Mickey that they must not panic, there is work to do. They ascend to find Jackie who hits the Doctor round the face before breaking into tears. The Doctor explains the beckoning apparition of Rose is a trick then tells Keisha to stay and look after her and a milkman they found dehydrated on the stairs. He warns her not to let Jackie out of her sight then descends to set to work, leaving Mickey confused as to what is on the Time Lord’s mind.
Rose walks along amidst the waters of the Thames and walks towards a large pipeline on one side of the river. She begins to walk inside, amidst many others who are all now members of the hive. Meanwhile, the Doctor and Mickey make their way to the London Underground and find a small cupboard leading to a service shaft, which passes down, inches away from the decontamination chamber where the creatures are hiding. Reluctantly Mickey follows him inside the tube and together they descend into the darkness.
As the sun slowly rises, Vida is taken to the reception of Stanchion House, where she fails to call Vice Admiral Kelper due to the fact her mobile phone has no battery. However Kelper has already heard of the chaos in London and arrives in the building where Vida tries to warn him that he is walking into danger. It is too late however; the water engulfs the floor and forms into a group of the ghosts who abducted her back at the laboratory, all of whom stand blocking their way out.
In a flooded pit deep below ground Rose stands remembering and calling out to people; Vida, who quietly cared, the Doctor in both his forms, Jackie, Mickey and Keisha. She thinks of them coming to join her before the start of the feast and how nice it would be. Sure enough in her flat she appears to Jackie and Keisha, calling to help.
As the Doctor and Mickey continue their descent in the large concrete tunnel, Crayshaw leads Kelper and Vida down into the decontamination chamber where the rest of the Stanchion House staff are waiting. Crayshaw watches as one of the walls is smashed and a wave of water floods in. All of them, including Vida and Kelper, are to be drowned before newness takes over.
As the water floods in the Doctor and Mickey arrive, knocking out the wall. As everyone there flees back up the tunnel has finds Vida and Kelper, who claims they will need Torchwood to resolve the matter. Suddenly the water around them freezes to ice and an angry Crayshaw advances on the Doctor.
Meanwhile, Rose is found by Huntley who warns her not to think about those she loves because they will be in danger. He explains he resists the will of the waterhive, as he has nobody to love, no family at all. He then explains to her in her ear what the ‘feast’ is, and she immediately feels sick. Back in the chamber the Doctor breaks free of the ice and as Crayshaw confronts him he realises the waterhive have laid eggs in the people they abduct, and during the feast of the drowned they will hatch and devour their host bodies. The Doctor swears to stop them then he and the others run for cover, but when they arrive in the ruined laboratory the Time Lord wonders if they believed him.
In the streets Keisha and Jackie are trying to get to the river and find a lorry, which someone has hijacked. They get inside as Keisha, in her mind, tells Jay and Rose they are coming to get them. In the Thames Rose and Huntley find Jay amongst the ranks of the drowned and he explains that he has appeared once more to Keisha and he saw what she was doing. She is with Jackie and they are on their way to the river.
The Doctor explains the waterhive need Kelper to organise ships to other country in order to spread themselves across the world. They will then travel via the hydrogen in the atmosphere and populate other worlds. He sends Kelper and several others to find some ships to block off the Thames. One of the soldiers, the one the Doctor stole a pass from, hands Mickey two grenades to defend themselves then leaves as the Doctor prepares to launch his stage of the plan to stop he hive.
Rose places an image of the TARDIS between her and Jackie to stop thinking of her as she realises that is Jay could see Keisha and Jackie through the eyes of his projection image it might be possible to send their own messages to the ones they love, but as she thinks the mental picture of the TARDIS fades and she sees someone other than Jackie standing beyond.
In the tunnel the Doctor is trying to resonate the concrete and find a way out but an image of Rose appears before them, feeding off of Mickey and Vida and warning them that if the Doctor interferes then his friends will die.
Rose fights the feeling of trying to call to her friends and tries to stop them hurting. Her apparition disappears as the Doctor realises that the signals and the conscious of the waterhive can be overridden. He remembers his tests on the water samples in the lab and how after he added some of the chemical tracers the water fought back. The tracers intercept the conscious of the waterhive and if Rose and the others can also override the signals the creatures would be beaten. Vida remembers that the Ascendant carried a store of tracers, which are now floating on the Thames.
Rose rejoices that she has warned the Doctor but there is more work to do. She appears to Keisha and Jackie in the lorry and warns them the apparitions are a trick. Jackie manages to stop the driver crashing into the Thames and then wonders what they are going to do as the air is filled with gunfire.
As the Doctor runs off to draw the water away from Mickey and Vida the two humans flee up a large staircase. Suddenly there is the gush of water as the hive follows them, flowing up the stairwell. They reach the top but the door is locked and their stolen ID card won’t work; leaving them left to watch the water approach.
Under the Thames Rose explains she has warned Jackie and Keisha then hatches a plan to get to the surface to warn the others what has happened. Huntley and Jay agree and begin rallying the others. Back in the stairwell the ID card finally works and Mickey and Vida run to the reception area where they use a broken door as a surfboard to ride around on the water, as well as one of Mickey’s grenades to create a wave of water to carry them over the turnstiles. They smash through the doors and out into the street, where the ancient water creatures are waiting for them.
The Doctor returns to the underground layer where Crayshaw and the others are waiting. He explains he wishes to make a deal with them. He will take the waterhive in the TARDIS to another planet to breed and the Earth will be left alone. As Crayshaw reveals the creature controlling him, a large one-eyed eel, his minions reach forward and grab the Doctor, he will not share his ship with them, they will take it from him.
Rose and the others arrive at the reception area of Stanchion House and threaten to kill themselves thus destroying the eggs they are carrying. The water creatures standing over Vida and Mickey go off to consult their leader and Vida tells Rose about the tracers. The young traveller decides to go with Jay to collect them, in the storage area they and the other drowned people were left to acclimatise after they were modified. As Vida, Mickey and Huntley stay behind to keep up the threat of killing the eggs, the hunt for the cylinders of tracers.
They arrive in the cargo trailer and find the crates containing the cylinders but they have been detected. Legions of the drowned approach, coupled with large sluggish monsters. They try to run but a blockade of water has been erected, about to drown the cargo trailer and send them back to the depths of the river. Meanwhile on the embankment, Jackie and Keisha are lost for what to do until Jackie is pulled from the truck and members of the thronging crowds take over. They smash through the barriers into the blockade and the crowd rush into the water, taking Keisha and Jackie with them.
In the cargo trailer Rose grabs hold of the crate as the wave blockade strikes. She holds on as she is pulled deeper and deeper into the water; she can hear Mickey and Vida calling out to her and Jay disappears from sight, leaving her to hold onto the crate and plunge down into the river.
From the side of the river, outside Stanchion House, Vida, Mickey and Huntley watch as Rose is pulled deep down into the river. They call out but realise it is too late; she and the sealed tracers are gone. Suddenly Commodore Powers appears with his cronies and they threaten to kill the carriers again. It is too late however as more of the water creatures appear and overpower them. Meanwhile, deep underground the Doctor waits as the queen of the hive positions herself on his neck. As the water apparitions let go of his arms the queen injects him in the neck, like so many who have drowned before.
As Keisha tries to resist getting trampled and pushed into the river she sees a little girl about to be killed by the crowd, who are rushing to get into the river. She reaches out, as Rose’s voice calls out to her to sort her life out, and tries to save the small child.
Vida and Mickey struggle to be let free and suddenly are joined by Rose, who is thrown up out of the river, still holding the crate of tracers. She explains the creatures must have known they were a danger and wanted to get rid of them. Vida manages to take hold of the crate and as Rose helps to fend off more of the drowned water creatures, Mickey hands her the remaining grenade and she jams it inside the crate. As she activates it she is thrown into the river by another of the drowned apparitions. Se struggles as the water seems to reject the crate and as the five-second fuse terminates, she prays all of their efforts were not for nothing.
As Rose ends up back in the water, sinking deeper, she feels a shockwave rush through the water and tastes a chemical tint to the water. As she worries about the Doctor, and if he will ever know what they achieved, she sees him in a vision, standing in a pool of water with one of the creatures attached to his neck. He places his hands on his temples and screams, as Rose looses sight of him and sinks deeper into the water.
As the Doctor allows his mind to meld with the queen’s, he begins to fight back. He sees into her mind, the mind of the hive that spreads across the water, feeding on love and longing. He sees the signals sent across the hive community and then he sees the chemical traces flooding across the water. He grabs them and activates them, scrambling the signals of the hive. As the queen screams out he screams with her and is cast into darkness.
In the river Jackie looks on as Keisha desperately tries to save the little girl before suddenly being pulled down into the water by some alien creature. She tries to tug free but something else intervenes. Suddenly the water bubbles, the creature lets go and she begins to rise to the surface of the river. Over the other side of the river, Vida also feels this and finds herself floating on the surface of the river. Soon Mickey and the others appear and Vida soon realises the water has gained a high salt content, and they are floating because of it, like in the Dead Sea.
As Rose appears, her gills healing and the alien vivisection being undone, she realises this is the Doctor’s doing, and sure enough he appears beside them, very weary and beaten, but alive. He explains that he used the chemical tracers to confuse the hive mind, to swamp the communication channels and leave them to fall to pieces. Now that the mind has gone, which was responsible for upholding the mutations inflicted on the drowned humans, are healing up. The salts in the water are the results of the creatures being broken down by the overload.
He explains that the salts will dissolve over time and the river will return to normal, before telling Vida that she and Andrew will have a lot of work to do, and as Vida feels the warm sunshine on her skin she agrees.
Later on, Keisha is fished out from the Thames and left on the wharf to recover. She sees Jay and together they embrace, lamenting that despite her phone call, it is unlikely their mother will return. They prepare to spend life together again, commenting how things can change it for the better or for the worse and they have to change with them, just like Rose with the Doctor.
The Doctor and Rose prepare to say their goodbyes. As Huntley and Vida prepare to start the clean-up operation Mickey tells Rose that nothing ever happened between him and Keisha. Rose says she believes him and soon Jackie is on the phone, calling from a pay phone by the river, explaining she met a man in the river who danced with her on the water-surface. She explains that Keisha and Jay are fine. As her money runs out she asks Rose if she will be back soon and as the line cuts out Rose whispers that she will. She turns and says goodbye to Mickey before sending a text message to Keisha to say farewell, before walking off with the Doctor towards new adventures.