The Doctor faces the end of his life as the Master's plans hurtle out of control. With the sound of drums growing louder, and an ancient trap closing around the Earth, the Doctor and Wilf must fight alone. But sacrifices must be made, and the deadly prophecy warns: "He will knock four times."
演员：克丽丝塔·B·艾伦 丹妮尔·查克兰 Jacob Young 贾里尔·怀特 Sam Boxleitner 玛克辛·巴恩斯 布莱恩娜·凯普 Brenda Arteaga-Walsh Katt Balsan Mary Kate Corsetti 杰夫·戴维斯 Braydon Joseph Ford Milena Phillips Courtney Rice Sallieu Sesay