For over a century human and Chelonian colonists have officially been at war over the planet Barclow, but a committee set up on Metralubit to look into the situation has yet to come to any conclusion, and as a result not a shot has been fired since the "conflict" began. Admiral Dolne and his opposite number General Jafrid have developed a healthy respect for each other's abilities, and are as close to being friends as enemies can be. After a failed series of peace talks on Metralubit, Dolne returns to Barclow to learn that an artist touring the disputed territory has returned with a wild tale about a missile strike wiping out his escort. Although contact has certainly been lost with the patrol, Dolne and his subordinate Hans Viddeas are sceptical of the artist's claims, and place him in confinement to prevent him from alarming the men. After all, why would the enemy possibly wish to open fire on them?
While exploring the TARDIS, Romana finds a device capable of forcing an emergency materialization just as the TARDIS impacts with the edge of the Time Spiral -- the furthest point of the Vortex, beyond which no TARDIS can safely venture. The Doctor uses the device to avoid destruction, and although puzzled by the odd coincidence, his curiosity is piqued by the distance he has travelled and he sets off to explore. The TARDIS appears to have arrived in a war zone, but the half-hearted nature of the missile strikes suggests that they are simply being fired for show -- at first. A genuine attack separates the Doctor from Romana and K9, and while trying to find his way back to them he finds the remains of human soldiers, their bodies coated with a preservative slime. He is then captured by a Chelonian patrol led by First Pilot Seskwa, who accuses him of conspiring to develop biological weapons and shows him the slime-coated body of a dead Chelonian soldier. The Doctor studies the body and concludes that the slime is the secretion of a predator which is meant to preserve the body for later consumption -- but Barclow has no native animal life.
Back on Metralubit, as Premier Harmock prepares for the forthcoming election, he receives unexpected and unwanted news from his personal Femdroid, Galatea; after a century of deliberation the Phibbs Committee is finally ready to publish its report on Barclow. Worried, Harmock contacts Dolne to warn him that his troops may be ordered into combat at any moment. Rabley, the Leader of the Opposition, is out touring the disputed zone to show support for the troops, but Dolne is unable to contact and warn him of the new situation due to a communications failure. The environment controls in the base are also malfunctioning, and the base is uncomfortably hot and swarming with flies. As the engineer sent to repair the environment controls has not yet reported back, Viddeas attempts to clear what appears to be a paper jam in the base's photocopier himself -- only to be killed and reanimated by a dark force which desires to escalate the war...
K9's sensors have been damaged by the bombardment, and as he and Romana search for the Doctor they stumble across the patrol escorting Rabley just as another bombardment begins. K9 tries to warn them of the danger, but Rabley doesn't comprehend that he's really under threat until it's too late. When the dust settles, Rabley is dead. Romana and K9 are taken back to the human base for questioning, but the hostile Viddeas throws Romana into prison. There, she is surprised to meet Menlove Stokes, the artist whom she and the Doctor met during the Xais incident. Stokes had himself placed in cryogenic suspension to await the inevitable acceptance of his genius, and he has found what he seeks on Metralubit -- and now that the situation on Barclow seems to be deteriorating he wants to return as quickly as possible. Dolne has them released, as the testimony of the survivors confirms Stokes' claims and proves that K9 attempted to save Rabley's life. As a result, the law of constitutional privilege gives K9 the opportunity to take Rabley's place as Leader of the Opposition -- and K9 chooses to accept, on the grounds that a position of power will better enable him to assist efforts to find the Doctor. Meanwhile, Dolne -- certain that the bombing was just a tragic error -- tells Viddeas to lightly bombard the Chelonian lines just to show willing, but Viddeas initiates a heavy artillery bombardment which wipes out a number of outlying Chelonian patrols...
Seskwa takes the Doctor to the Chelonian base, where he learns that these Chelonians, descended from a group of colonists stranded on a barren planet by a temporal anomaly, have long since lost their aggressive tendencies. Jafrid feels that Dolne is not foolish enough to start a shooting war, particularly one he knows he cannot win, and therefore allows the Doctor to analyse the slime from the dead Chelonian's body. The Doctor finds proof that it was genetically engineered, which supports his growing theory that a third party is trying to escalate the war. Jafrid allows the Doctor to contact Dolne with his findings, and Dolne puts him in touch with Romana and K9 -- who is now committed to run in the election and cannot back out. Seskwa agrees to take the Doctor to the human base to negotiate a new peace accord, but on the way back Seskwa tries to drive the tank over a cliff, and the Doctor realizes that Seskwa is dead, his body reanimated by the third force. The Doctor escapes from the tank just in time, but the Chelonians detect the tank's destruction and Jafrid concludes that the Doctor has betrayed them. Meanwhile, Viddeas -- now nothing more than a walking cadaver buzzing with flies -- attacks and kills Dolne. The Darkness then passes from Viddeas into Dolne, who returns to the command centre and orders a missile strike. The Chelonians respond in kind, and the war begins in earnest.
Romana, K9, and the desperate Stokes have already departed for Metralubit, where K9 begins his political campaign. Harmock is horrified when the colonists appear to respond favourably to K9, but news of the war soon reaches Metralubit, and K9 and Harmock find that panic-stricken riots are breaking out all over the world despite their pleas for calm. Romana, meanwhile, is puzzled by certain technological discrepancies she has noticed; the Metralubitans possess Fastspace technology but do not have transmat capabilities, and the Femdroids appear to operate upon exactly the same principles as K9. Hoping to find an explanation in the history of the planet, Romana soon makes a terrifying discovery -- every two thousand years a planet-wide civilisation has collapsed amidst destruction and death beyond counting, and the last such disaster took place two thousand years ago. Romana takes her discovery to the Femdroid Liris, who insists that she must be mistaken -- and then secretly reports to Galatea that the great plan is in danger. Meanwhile, Stokes tries to leave the government building to rejoin his friends and admirers in the city beyond, but finds that he cannot remember the way out -- and when he tries to force his way onwards, he descends into a trance and is taken by Galatea and Liris for further mental processing to reinforce his conditioning.
The Doctor falls into an underground cave system while trying to avoid the bombardment, and there he meets Fritchoff, a political protestor who, as far as he's concerned, represents the interests of the proletariat of Metralubit. When the Doctor searches for Fritchoff's fellow protestors he finds them dead, their bodies coated with preservative slime -- and is then confronted by a buzzing swarm of flies, and realizes that he has travelled so far into the future that the flies have evolved into a group organism capable of telepathy and telekinesis. Forced out of their ancient feeding grounds by the Time Lords, the Hive has been manipulating this isolated human colony for millennia, creating a cycle of death to provide themselves with carrion on a regular basis. The Doctor takes Fritchoff to warn the others of the true threat, but they are captured by the Chelonians and taken back to Jafrid. Fritchoff is dismissed as unimportant and manages to stay out of the Chelonians' way, but the Doctor stands accused of conspiracy and betrayal, and is placed in the Web of Death -- a torture device designed to stretch his limbs until they separate from his body.
Galatea realizes that Romana will not abandon her investigation, and attempts to erase the memory of her discovery. Romana, however, only pretends to fall victim to the conditioning, and as soon as she is released she takes K9 and Stokes to warn Harmock of the conspiracy. Galatea, telling the disturbed Liris that she is acting on behalf of a higher power, sends a squadron of Femdroid assassins to kill Romana, and K9, still damaged from the battering he received on Barclow, is unable to defend her. The panic-stricken Stokes tries to escape and finds his way to the Femdroid control centre, where he fulfils a promise made some time ago and smashes it to bits with a hammer. Femdroids all over the city collapse, and as they expire, so does the holographic illusion of the outside City, which in reality is completely deserted. The results of the phone-in polls, the news broadcasts and the images of the rioting population were all faked by the Femdroids, and K9 was unable to perceive the truth due to the damage to his sensors.
A recorded message from Galatea is activated, revealing the truth; Stokes was in fact found and partially revived centuries ago by a team of scientists who analysed the memories within his dormant brain and thus made a quantum leap in their planet's technology. Even the Femdroids were created based on his memories of watching Romana repair K9 on the Rock of Judgement. This unexpected event broke the cycle of death caused by the Hive, as this civilisation was the first to develop artificial intelligences capable of discovering the Feeding Cycle and deducing the reason for it. Under Galatea's guidance, the Femdroids constructed a mass transmat, sent the population of Metralubit to safety in another solar system, and then put in motion events which would lead to the destruction of the Hive. The conflict on Barclow and the supposed riots on Metralubit were apparently leading to the collapse of civilisation once again -- but once the Hive descended upon Metralubit to feed, the Femdroids intended to have the soldiers on Barclow bomb Metralubit and thus destroy the Hive forever. Now, thanks to Romana, the Hive will realize that it has been deceived. Horrified by what she has done, Romana sets off back to Barclow to put things right, accompanied by Harmock, K9 and the disillusioned Stokes -- who realizes that he was lied to when promised he would find a civilisation which truly appreciated his art.
The failure of the Femdroid control centre has caused a complete communications breakdown on Barclow, and Dolne leads his troops out for the final battle -- final in every sense, as the furious Hive has discovered the truth and is preparing to devour every living thing on Barclow. As Jafrid departs to face his enemies, he salutes the agonised Doctor's honourable death; but Fritchoff, who had been unwilling to interfere in the Chelonians' due legal processes, nevertheless opposes the concept of honour in war and thus releases the Doctor. The Doctor rushes to the battlefield and points out the Hive as it descends upon them all, and Jafrid realizes that the Doctor has been telling the truth all along. The Darkness within Dolne attempts to possess the Doctor in order to gain access to his TARDIS, but K9 shoots him, causing the flies in his body to scatter temporarily. As Stokes flees in terror, the Doctor uses K9 to transmit a message to the people of Metralubit, telling them to destroy their transmat system to ensure that the Hive cannot use it to transport itself to a heavily populated sector of the galaxy. The Hive picks up the transmission and immediately sets course for Metralubit, but before it arrives the Doctor is able to remotely reactivate Galatea, whose power source and memory chips are self-contained and operate on the same frequencies as K9's. Following the Doctor's instructions as relayed by K9, Galatea inverts the co-ordinate settings on the transmat, and when the Hive descends upon Metralubit it is thus transported it into interstitial space, where it will remain until the Doctor can dispose of it with the TARDIS.
All seems resolved, but the Doctor is concerned by the level of coincidence at work, and is beginning to feel as though he's been manipulated. Humans and Chelonians should not exist in any recognisable form this far in the future, and the fact that there are plausible explanations for their presence only serves to heighten the Doctor's anxiety. When Romana reveals that Menlove Stokes is present, this only convinces the Doctor he is right, and he rushes Romana and K9 back to the TARDIS to collect and dispose of the Hive before the trap is sprung -- unaware that this act is itself the final part of the trap. Stokes, desperate to escape from the Hive, has already located and entered the TARDIS, and once inside, has accessed its data banks and learned that he is destined to become a professor of art at St Oscar's University on the planet Dellah. Following the instructions whispered from a crystal provided by his benefactor, Stokes sets the co-ordinates for Dellah in the 26th century -- and when the Doctor bursts in, he is in such a rush to escape that he picks up the Hive without checking the co-ordinate settings first. When he does so, he realizes that they are locked off; he cannot materialize anywhere but 26th-century Dellah, and doing so will release the Hive upon the heavily populated past. His trap sprung, the Black Guardian materializes on the scanner screen and confirms that he has manipulated events to put the Doctor in a position where he must either release the Hive upon the galaxy or accept eternal exile in the Time Vortex, never to materialize again. The Black Guardian transports Stokes to Dellah as promised, and settles back to await the Doctor's decision -- but much to the Guardian's shock, the Doctor chooses to operate the emergency cut-out switch and take the TARDIS out of real time and space altogether, possibly never to return...
Source: Cameron Dixon