In Cardiff, the dead body of a young male lies in a pool of blood in the torrential rain, surrounded by police officers and forensic scientists. WPC Gwen Cooper arrives on the scene and joins her partner PC Andy. The identity of the murder victim is not yet known, but before the investigators can go about their work, everyone is suddenly told to leave the area. The situation is confused and no one really seems to know what’s going on, but Gwen is told they’ve received orders from above to clear the site to give access to a Special Ops unit called Torchwood. At that moment, a vehicle arrives and four people in civilian clothes, led by Captain Jack Harkness, emerge and quickly take control of things. The police are furious about the possible contamination of evidence, but there’s nothing anyone can do. Gwen slips away and goes to an upper floor of the nearby multi-storey car park so she can watch the new arrivals unobserved.

While his colleagues set up equipment around the dead man, Jack tells them he can taste estrogen in the rain, no doubt caused by the Pill being flushed away, then entering the water cycle and leading to contraceptives in the rain. At least he won’t get pregnant - he never wants to do that again! The others are ready and one of them, Suzie Costello, puts on a strange metallic glove. They’re obviously waiting for something to happen, but the glove hasn’t ‘connected’ yet and Suzie says they have to wait for it to grant her access. Just then, the glove links with her and the group move into pre-set positions around the body. The third member of the group, a young man named Owen Harper, warns Jack that if he gets punched again like last time, he’s going to punch back.

Suzie gently places her gloved hand behind the head of the dead man and strange things begin to happen. First, the torrential rain stops instantly and then the lights around the area start to flicker. Then the eyes of the dead man open! Gwen watches from above in horror as the young man comes back to life and finds himself lying on the ground surrounded by strangers. The fourth member of Jack’s group, Toshiko Sato, tries to calm him and explains they only have two minutes. She tells him he’s dead, the victim of a single stab wound in the back, but she wants him to identify his killer. Sixty seconds left… Unfortunately the man can’t tell her anything as he was attacked from behind. Thirty seconds… Toshiko is lost for words, so Jack steps in and introduces himself. He asks the man what it was like when he died, what did he see? Ten seconds… The victim, John Tucker, replies that he didn’t see anything…and then he dies again. The torrential rain starts again, just as suddenly as it stopped. The group argue about whether it was a good idea to tell the man he was dead, but when they told the last victim he was only injured he spent the whole two minutes screaming for an ambulance. Perhaps there isn’t a right way to do this. Captain Jack suddenly looks up at Gwen and asks he what she thinks. Gwen jumps back in shock and races away from the car park.

As soon as she’s clear from the area Gwen stops for a moment and tries to make sense of what she’s seen. Later, she returns home and finds her boyfriend Rhys Williams sprawled out on the sofa watching television. They discuss normal, everyday things (including an old friend who dropped by earlier, and the rapid approach of middle age) and then Gwen goes to bed. But this was not a normal day for her and she cannot sleep.

The next morning at the police station, Gwen asks a colleague Yvonne to do a search for Captain Jack Harkness on the police database. Then she attends a briefing chaired by Detective Inspector Jacobs, who’s in charge of investigating three recent murders. All the victims, Sarah Pallister, Rani Ghosh and John Tucker were stabbed with the same weapon, but so far there’s nothing else to link them together. Gwen and Andy are called out to another job and on the way they discuss Torchwood. All anyone knows is that they’re Special Ops, which to Andy means they’re probably DNA specialists. They enter a pub and find themselves right in the middle of a massive brawl. The police officers get stuck in, but unfortunately Gwen is knocked back against a wall and badly hurts her head. Gwen is examined by a doctor at the local hospital and is given the all clear, but as she leaves, she spots Captain Jack racing up the stairs and she decides to follow. She reaches the top of the building, and is surprised to find Jack gone and the whole of the top floor cordoned off with police tape. She asks a passing porter if he knows anything about it, but all he can tell her is that the police sealed the area off earlier that morning. Something to do with chemicals, he thinks. Gwen decides to investigate further and steps nervously through the tape.

She finds herself at the end of a long empty corridor. She calls out, but no one answers. Then a figure slowly shuffles out of a doorway at the far end. She can’t see him clearly from this distance, but as she cautiously approaches, she starts to realise there’s something odd about him. He’s dressed in a dark shiny boiler suit and is slightly hunched. But it’s his face that draws her attention. The closer she gets, the more it becomes clear that this is not a human face. It appears to be some sort of monster with furrowed ridges and large sharp teeth. As Gwen tries to question it, the hospital porter arrives with more information about the cordon and he too sees the creature’s face. He believes it’s a brilliant mask, like those seen in the film “Hellraiser”, but as he approaches the creature, it suddenly attacks him, biting straight through the jugular. As Gwen backs away in horror, Captain Jack and his colleagues burst out of a lift, and while he leads Gwen away, the others join forces to overpower the creature and capture it.

Gwen races downstairs and finds herself back in the main hospital, where everyone else is going about their business as usual. In the car park, she sees Captain Jack and the others being driven away in a vehicle with blackened out windows. She races to her police car and gives chase. As she pursues them across Cardiff, she radios through the licence plate number of the vehicle and finds it’s not registered. Her colleague Yvonne has completed the search on Captain Jack Harkness and reveals that the only person with that name and title was an American volunteer who went missing from RAF 133 Squadron on January 21st 1941 at the height at the Blitz. Gwen follows the vehicle to the Canolfan Mileniwm Cymru, also known as the Wales Millennium Centre, but as Jack’s group stroll towards the building she is distracted for a second and when she looks back, they’ve disappeared without a trace. PC Andy arrives, having walked there all the way from the hospital. She tells him about the death of the hospital porter, but when he checks he finds that all the staff have been accounted for. In any case, her boss is livid that she’s not reported back for duty. As Andy takes her home, they’re unaware that their every move is being watched from a scanner on top of the Millennium Centre.

Later, Rhys has cooked a meal for Gwen, but she pretends she’s been drafted in to do a second shift and will be working all night. However, she returns to the area where Jack and the others disappeared and continues her search. Before long she sees a local pizza delivery rider passing by, which gives her an idea. Still unaware that she’s being watched, she goes to the pizza shop and asks them to check whether a ‘Jack Harkness’ is one of their customers. He isn’t, but her second guess is more lucky - the shop receives regular orders from Torchwood. Later still, she arrives at the address she was given and enters a small tourist information office posing as a pizza delivery girl. A young man in a suit, who she’s not seen before, asks who the delivery is for and when she gives Jack’s name he operates a control which locks the door. Then the entire back wall of the office glides open and he tells her to go inside. She finds herself in a long, dark brick-walled corridor which ends with a lift. She enters and the lift starts to go down.

Still carrying the pizzas, she leaves the lift and emerges into a gigantic room, consisting of several storeys, which appears to be a cross between a futuristic laboratory and a workshop. She sees many strange objects dotted around, including a disembodied hand kept alive in a tank The group she saw are all engaged in separate projects, but none of them reacts to Gwen’s presence - even Captain Jack who comes down from an upper floor and walks straight past her. Eventually the pressure of acting nonchalantly becomes too much for some of the group and they burst out laughing. Giving up any further pretence, Jack rebukes them for spoiling the joke before he was able to deliver the punchline, and also for being negligent enough to order pizzas under the name Torchwood! The group admit they’ve been watching Gwen walking around outside for the last three hours. She asks about the hospital porter and Jack admits he is dead. However, they’ve taken the body, retrospectively changed his work rota, planted a false witness who saw him leaving the hospital and given him an alibi for the next 48 hours, so that when his body is eventually pulled out of the docks next Tuesday he’ll have only been missing for three days.

As a pterodactyl flies overhead, Jack takes Gwen down to the basement to meet the porter’s killer. He shows her into a cellar lined with cells made of reinforced glass. In the end cell she sees the creature from the hospital. Jack tells her it’s a Weevil, or at least that’s what Torchwood call it. There are a couple of hundred of them living in the sewers beneath Cardiff, but every once in a while one of them goes ‘rogue’ and comes to the surface to feed off people. It’s been happening more and more recently and nobody knows why. It’s an alien, born on another world - and it‘s real!

Jack takes Gwen back to the others in the Hub and introduces them formally. Dr Owen Harper is an all-round genius, Toshiko Sato is their computer expert, Suzie Costello is their hardware specialist and is second-in-command, and Ianto Jones, the man who she saw in the tourist information office, is the one who looks after them and gets them where they need to be on time. Gwen realises she’s been given far too much classified information for her own good and wonders what they’re planning to do with her. Jack gives everyone last minute instructions, then they all bid each other goodnight and close down Torchwood for the night. Gwen is then led to a large flat stone on the floor and when she and Jack step on it, it becomes a lift that carries them both up to the ceiling…and then directly outdoors where they finds themselves at the foot of the Wales Millennium Centre. It’s a busy night but people are passing by without noticing anything untoward and Jack explains that it’s a perception filter. While they‘re standing on the stone they won’t register fully with people, as if they’re only faintly aware of seeing something out of the corner of their eye. He doesn’t know exactly how it works, but he suspects it had something to do with a dimensionally transcendental chameleon circuit that was once placed on the spot and had its properties welded to a spatial-temporal rift.

Jack takes Gwen for a drink in a nearby bar. He knows exactly what she’s going to ask, and jumps in first to ask why she doesn’t believe in aliens after everything that happened on Christmas Day in London, the battle of Canary Wharf and Cybermen in every home. Gwen’s boyfriend had already worked out that this was probably the result of terrorists putting hallucinogenic drugs in the water supplies. Jack thinks he sounds very stupid. The members of Torchwood catch aliens for a living, but they also scavenge the things they leave behind and find ways of using it to arm the human race for the future. The 21st century is when everything changes and Earth has to be ready. Torchwood is kept separate from the government, outside the police and beyond the United Nations, in order to prevent anyone getting access to their technology. Gwen wonders whether they can be trusted themselves, but he assures her none of them are allowed to take anything out of the base. Unfortunately, Jack is unaware that at that precise moment his team are already doing exactly that! Toshiko has taken home a strange device that can ‘scan’ an entire book in seconds and then download every page onto a computer, Owen is preparing for a night on the town and has brought with him a odd looking phial of ’aftershave’, and Suzie is experimenting with the metal glove, bringing a dead fly back to life.

Jack explains that the base in Cardiff is actually Torchwood 3. Torchwood 1 was in London, but it was destroyed during the battle of Canary Wharf, Torchwood 2 is in Glasgow and is run by a very strange man, and Torchwood 4 has gone missing, but they’re hoping to find it again sometime soon. They’re based in Cardiff because there’s a rift in space and time running right through the city. The Weevils didn’t arrive in a spaceship, they just slipped through the rift. All sorts of things get washed up here: creatures, time shifts, space junk, debris. Gwen wants to liaise on the murder investigation, but Jack reveals they weren’t at the scene of the crime to track the killer but simply to test the alien glove. They have no interest in this case, they were only looking for freshly-killed murder victims because the more violent the trauma, the stronger the resurrection becomes. They’re too busy to help the police and they believe their work is more important. Gwen refuses to accept this and says she has a duty to tell the police about the glove. Jack says she’ll only be able to do this if she remembers…and he then asks if she enjoyed her drink. Gwen thinks she’s been poisoned, but he reveals he used an amnesia pill “with a touch of denial and a dash of ret-con“. When she wakes up in the morning she’ll have forgotten everything about Torchwood, including him.

She moves to leave, but Jack tells her there was also a sedative in the drink and she’ll be asleep soon. As he disappears into the night, Gwen manages to make the journey home in extra-quick time and rushes to her computer where she types in hints and clues about Torchwood that she hopes will prompt her when she wakes up. But back at the Hub, Ianto has hacked into her computer and he manages to delete everything, just as she finally drops off to sleep.

Meanwhile, Owen is also visiting the pubs and bars of Cardiff City. He sees a young woman who interests him and makes a very weak attempt to chat her up before deciding he couldn’t be bothered to make the effort. Instead, he sprays himself with the alien ’aftershave’ and the woman immediately falls in love with him. She drags him out of the bar, but they’re stopped by her boyfriend who is ready to beat Owen up. Owen sprays himself again - and the husband also falls in love with him. As both the man and the woman fight over who is going to sleep with Owen first, he summons a taxi.

The next morning Gwen arrives at the police station and Yvonne asks her whether she had any luck tracing Captain Jack. Unfortunately Gwen doesn’t know what she’s talking about. In the incident room, she discovers the murder investigation has had a lucky break. Apparently the computer guys have come up with an accurate drawing of the murder weapon, a strange looking ornamental blade. She finds the picture oddly familiar, but she doesn’t know where she’s seen it before. Over the next day and night, Gwen can’t shake the image of the blade out of her head and she starts getting flashbacks. Then, she discovers a note that she’d hand-written the night before that simply says “remember” - and it’s written on the cover of a tour guide promoting the Wales Millennium Centre.

She returns to the Millennium Centre and tries to work out why it seems some familiar. From the shadows, another figure emerges - it’s Suzie Costello. Suzie tells Gwen she was right to suggest liaising with the police, and it was she that sent them the drawing of the blade. She gets the murder weapon out of her bag and Gwen realises that Suzie is the killer herself! Suzie had guessed that Gwen saw the knife during her visit to the Hub and she knows that one strong image is sometimes enough to override the amnesia. Realising that Gwen will put up a fight, she pulls out a gun. Torchwood will find out the truth about Suzie by the morning, but she plans to be gone by then. Gwen is the only other person who can make the link, so she must be killed. Suzie breaks down, confessing that she really loves her job, but it gets inside your head if you do it long enough. She thinks that alien life is filth, but maybe there’s better stuff - brilliant, beautiful stuff - still out there, waiting to be discovered. But this planet is so dirty it only seems to attract the nuts. She admits that she murdered the three people just so that she could experiment with the alien glove. The more killings she commits, the more control she has over the glove, so just think what she can do if she can get the glove to resurrect people permanently, not just for two minutes.

While they’re talking, Captain Jack slowly appears between them, standing on the perception filter stone which is rising out of the ground. He listens sadly as Suzie confesses to her guilt, admitting that she surrendered herself completely to the knife - and that is why the perception filter doesn’t work on her. Without warning, she swings round and shoots Captain Jack between the eyes. He falls to the floor, dead, and as his body drops off the stone, Gwen sees him for the first time. Suzie then turns the gun back to Gwen, but as she’s about to shoot her too, the dead body of Jack rises behind her and his gunshot wound miraculously heals itself. Realising it’s all over, Suzie decides to end it all and shoots herself in the head. As Gwen remembers everything, she falls to her knees in shock.