The Omega device is in jeopardy. A giant Dalek warship hangs above the Earth. London has become a battleground for ruthless alien intelligences.

London, 1963. Returning to the scenes of his first televised adventure, the Doctor and new companion Ace play a tricky game of bluff and deceit involving two rival Dalek factions, local soldiers, and the awesomely powerful Gallifreyan artefact, the Hand of Omega...

With two factions of Daleks involved in a race war on Earth, the Doctor takes care of old business by having the Hand of Omega ceremoniously but quietly buried in a churchyard. His actions do not go unobserved, and leaving behind a bored Ace without a purposeful outlet could spell trouble as well.

The Doctor plans to let one of the Dalek factions have the Hand of Omega (but not too easily, of course) while keeping Gilmore and his military men preoccupied in a safe territory, but that plan could be threatened by a mole in their midst and a miscalculation on the Doctor's part.

The Doctor and Ace visit the Psychic Circus on the planet Segonax, where they find the standard of judging at the talent contest distressingly astringent.

The Doctor and Ace reach the Psychic Circus, where the Doctor is imprisoned with the other contestants while Ace draws the attention of the Chief Clown.

Mags helps the Doctor escape and Deadbeat leads him to Ace, where Bellboy tells them what happened to the Psychic Circus.

Mags goes to find Ace and Kingpin, pursued by the Chief Clown, while the Doctor confronts the power behind the Psychic Circus.

The Earth colony Terra Alpha, the future. With the aid of her sweet-natured executioner, Helen A, ruler of the planet, has ensured the population is happy - on pain of death! The Doctor and Ace decide to fight for the right to be miserable.

As the Doctor leads the Pipe People towards reclaiming their world, Helen A faces betrayal from those closest to her.

The Doctor and Earl manage to escape from the Kandy Man and join up with the planet's natives, the Pipe People, enlisting their help to rescue Ace.

The Doctor and Ace battle the time traveller Lady Peinforte and the Cybermen for possession of the incredibly powerful Nemesis statue, which is on its way back to the planet Earth to rendezvous with a destiny set in stone by the Doctor himself.

As hostilities break out between factions vying for ownership of the comet, the Doctor goes after the worst of the lot - Cybermen, using Ace's upgraded boom box to flood Cyber Communications with jazz music while trying to locate the whereabouts of the fleet beyond this mere scouting party.

With the Cyber Fleet poised nearby, the Doctor may have no choice but to let them have Nemesis. Meanwhile, Lady Peinforte and Richard navigate modern society, De Flores encounters an open betrayal, and Ace combats Cybermen with a slingshot.