All six parts of the classic Doctor Who story, with Tom Baker playing the legendary Time Lord as he faces up to his greatest enemy - the Daleks. Charged by the Time Lords with the task of destroying the Dalek menace before they have even developed, the Doctor travels with Sarah (Elisabeth Sladen) and Harry (Ian Marter) back in time to the planet of Skaro, to a point where he could prevent the evolution of the Dalek race. But the Doctor faces a crisis of conscience as he questions the ethics of what amounts to genocide. Will he be able to destroy an entire species to save countless lives in the future?