Many incarnations of the Doctors and their old companions are taken out of time and deposited in the Death Zone on Gallifrey. There, they must battle the Master, Daleks, Cybermen and Yeti in order to reach the Dark Tower and discover the Tomb of Rassilon.

Freed at last by death from tyranny of an elderly, querulous mother, Esme Fanshaw is persuaded to take a man, Amos Curry, into her house as a paying guest. At first wary of him, Esme becomes increasingly fond of this dapper little man with his mysterious summer occupation. When she finally learns the nature of this occupation she is at first shocked then sympathetic.