Plot
Captain Britain and Jackdaw are transported from Otherworld to Earth-238 by Merlyn, immediately stumbling on a bank robbery being committed by Mad Jim Jaspers and the Crazy Gang, driving them off. They soon find they are in a Britain where the population are downtrodden and impoverished under the totalitarian British National Party, police are armed and superheroes are banned. Captain Britain successfully saves London from an attack by a strange animated junkyard creature but the feat fails to convince the authorities, particularly the brutal armed paramilitary Status Crew, of his good motives. He finds a mysterious liquid that has created an intelligent rat called Algernon, and traces the source to Majestrix Saturnyne of the Dimensional Development Council. She and her agents the Avant Guard are attempting to use life-enhancing fluid to advance the development of Earth-238, which is so regressive it is corrupting other parallel worlds. Having seen the miserable people of Earth-238, he agrees to help her with the push. Captain and Britain help the Avant Guard distribute the fluid, which has an immediate effect. However, at the moment of the push itself Jaspers uses his mutant reality-altering power to twist London into a nightmare.
Believing Captain Britain is responsible, the Status Crew unleash the Fury, a bio-mechanoid that had previously purged Earth-238 of superhumans. Saturnyne and the Avant Guard abandon them and Jackdaw is killed. The Fury is impervious to Captain Britain's furious attacks and easily breaks his arm. After a surreal encounter with the Fury's creator Jaspers he finds himself in a graveyard for the Fury's victims and berates Merlyn for sending him to such a place before the Fury obliterates him. Merlyn and Roma recover his remains and rebuild him in Otherworld and return him to Darkmoor on Earth-616, unaware of his death and resurrection. He returns to Braddock Manor and finds it has been rebuilt by Mastermind; after the computer attempts to talk him into suicide he is able to reprogramme it to be more benevolent. Soon after he receives a phone call from his sister Betsy in London. She has put her telepathic abilities to use as a member of S.T.R.I.K.E.'s Psi Division, but it had been infiltrated by agents of Vixen, and now Betsy and her friends are under attack from the hired assassin Slaymaster. Captain Britain is able to defeat Slaymaster after a battle on Denmark Street, and takes Betsy and two other surviving telepaths – her lover Tom Lennox and their friend Alison Double – back to Braddock Manor.
Soon after he is abducted by the Special Executive and reluctantly taken to the Dimensional Development Court, where Saturnyne is on trial for her alleged failures on Earth-238. Despite her deserting him he feels compelled to tell the court of Jaspers – but is infuriated when Judge Lord Mandrake simply wipe Earth-238 out of existence, and is able to act as judge and prosecutor at Saturnyne's trial. He comes into conflict with the members of the Captain Britain Corps acting as bailiffs, leading to the Special Executive coming to his aid and helping to evacuate the hero and Saturnyne back to Braddock Manor. There they are visited by Linda McQuillan – formerly Captain UK, the equivalent to Captain Britain of Earth-238 and now sole human survivor of the planet. She was sent to Earth-616 by her late lover and is alarmed to find the dimension's version of Sir James Jaspers is espousing exactly the same firebrand anti-hero rhetoric that led to the purge in her home dimension. However, it is soon revealed that something else escaped the destruction of Earth-238 – the Fury. It attacks Linda, who is saved by Merlyn's intervention, then aided by Captain Britain and the Special Executive. However, in the resulting battle two members of the Executive are killed, leader Wardog has his cybernetic arm torn off and further casualties are only avoided when the Fury is briefly unable to register Zeitgeist, giving Captain Britain and Fascination the chance to bury the machine. At Zeitgeist's insistence Wardog then reluctantly orders the Special Executive to leave.
Jaspers meanwhile has rapidly seized control of Britain, with S.T.R.I.K.E. having rounded up anyone with any hints superhuman talents into concentration camps. Captain Britain and his remaining allies head to London to help but are largely forced underground, with Jasper's warping abilities causing problems for Allison and Betsy, and Linda still traumatised by the return of the Fury. Vixen meanwhile attempts to assassinate Jaspers before he attracts the attention of The Avengers or S.H.I.E.L.D., but he is too powerful and simply turns her into a docile animal. Captain Britain sets off to confront him but Jaspers' enforcers kill Tom before capturing Betsy and Alison. Despite his best efforts, Captain Britain finds Jaspers' ability to change reality on a whim makes him impossible to fight, and things get worse when the Fury – having escaped the chasm near Braddock Manor – arrives. After trouncing the hero it moves on to Jaspers, who has also created a new Crazy Gang. Realising that the immunity the mutant's Earth-238 version built in does not apply to the Earth-616 version, the Fury attacks Jaspers and a reality-bending battle begins; their duel causes so much damage to reality that Merlyn is killed. The Fury finally transports Jaspers to un-space, where there is no reality for him to alter, and is able to kill him. Returning to Earth-616 drained, it is attacked by Captain Britain. When the damaged machine fights back Captain UK – snapped out of her malaise by Saturnyne – finishes the Fury off.
The crisis is over, and Roma transports Captain Britain, Captain UK and Saturnyne to Otherworld to attend Merlyn's funeral with the rest of the Captain Britain Corps. After the ceremony she reveals to Captain Britain that Earth-616 is already rapidly healing from Jasper's warp, and that Saturnyne has returned to the Dimensional Development Council, rapidly blackmailing her way back into power. She then returns Brian and Linda to Darkmoor, where they briefly kiss before parting.