"Europa is infested by ghosts, vampires, werewolves, ghouls and other grotesques spawned from old European folklore. I think we're in a spot of bother, Sarah."
Europa, designed by lunatics a thousand years in the future, is a resurrected Europe that lives in an imaginary past.
In Europa, historical figures live again: Lord Byron combats Torquemada's Inquisition, Mary Shelley is writing her sequel to Frankenstein and Cardinal Richelieu schemes to become Pope Supreme while Aleister Crowley and Faust vie for the post of Official Antichrist.
When the Doctor and Sarah arrive, they are instantly accused of murdering the Pope. Aided only by a young vampire hunter and a revenant Byron, they confront the sinister Theatre of Transmogrification in their quest to prove their innocence.