在时间尽头，命运交织，博士与同伴共同面对宇宙的终极考验。思春期性学习

　　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."