The Doctor agrees to meet his old foe the Master on the planet Tersurus. But when the Doctor arrives, assisted by the lovely Emma, the Master has prepared a series of hideous tortures for them. Horrible tortures. Evil, nasty and decidedly unpleasant tortures...

As the Doctor and the Master attempt to outwit one another a bizarre odyssey unfolds, featuring treacherous trapdoors, bottom burps, foul-smelling sewers and the infamous sofa of reasonable comfort. When the Daleks become involved a series of mishaps trigger the Doctor's regeneration cycle, leading to the biggest and most exciting adventure of his lives!