Zagreus is a 2003 Big Finish Productions audio drama based on the long-running British science fiction television series Doctor Who.

This audio drama was presented on three compact discs, and was made by Big Finish as their primary release to celebrate forty years of Doctor Who.

Following directly from the events of Neverland, the casket of anti-time which was destined for Gallifrey had exploded within the confines of the TARDIS.

Charley finds herself in Harley Street talking to her mother Lady Louisa Pollard, who mentions amongst other out of place information that one of her sisters is called Romana.

Charley is taken to see a Dr Zagreus, and her mother turns into a white rabbit from Alice's Adventures in Wonderland.

The Doctor leaves the library through a secret passage and finds a part of the TARDIS unaffected by the anti-time infection, from where he is able to converse with Zagreus.

Miss Foster, who had told Charley and the Brigadier that she was a military secret agent, tries to plant a bomb on the Dionysus project; she was in fact a spy for communist Cuba.

On ancient Gallifrey, the Great Mother, Cassandra, Provost Tepesh and Lady Ouida discuss why their groups despise Rassilon.

The Dionysus Project that Charley saw at Cardington had breached the loop, allowing creatures from the Divergent universe to enter ours.

The Great Mother reveals that Rassilon stole the secret of regeneration from the Vampires, and that much of Time Lord technology was stolen from the Divergent universe.

The Foundry's defences seal off the whole base and prepare to fire storm it to prevent the escape of the Divergent creatures.

To his horror, he discovers he has been in suspended animation for 60 billion years and has awoken on the dead world of Gallifrey, which the theme park was moved to.

They revived Winky to operate the controls of the Foundry machines, but he dies of the heart condition which he had entered suspended animation to survive.

Rassilon's spirit speaks through Leela, and leads them to a Matrix simulation of the Dark Tower in ancient times.

Meanwhile, Charley informs Townsend, Tepesh and Winky that they are Zagreus's recreations of the Fifth, Sixth and Seventh Doctors, and also the only people to have ever seen the Divergence.

Rassilon summons the Doctor and the Brigadier into the Foundry, which he proudly declares to be the place where he created the Nemesis and the De-mat gun.

Rassilon shows them a frozen solar system — one which housed a species which could have threatened the Time Lords.

From the Dark Tower, Romana, Charley, the Doctors and a K-9 find a secret entrance to the Foundry through the mirror.

Townsend cracks a code in Old High Gallifreyan, proving they were created from the Doctor's memories and thus retain some elements of his knowledge.

Pushing past the Brigadier, they find the Doctor by an anvil creating a sword from the molten TARDIS shell.

The Doctor does not regenerate, however; when Rassilon killed Townsend, Tepesh and Winkle those parts of him were removed, and when Charley stabbed him they were restored saving him from death.

Charley storms out of the TARDIS, whereupon Romana speaks to the Doctor telling him that he will never be allowed to return and the Time Lords will prevent him from doing so if he tries.