Zagreus sits inside your head.
Zagreus lives among the dead…
Zagreus sees you in your bed
And eats you when you're sleeping.

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. It seems that the Eighth Doctor and Charley have saved Gallifrey, and that the paradox of Charley's existence had been resolved, but the Doctor begins behaving strangely — he has been taken over by Zagreus.

Chronological Placement: This story takes place after the 1996 Doctor Who TV Movie and after the Big Finish audio adventure Neverland.