The TARDIS materialises in a hostile jungle on the planet Spiridon. Jo sets out alone to find help for the Doctor, who has fallen into a coma. She meets a party of Thals and is left in hiding aboard their crashed spaceship while they go to the Doctor's aid. The Time Lord, now recovered, learns of their mission to destroy a party of Daleks sent here to discover the native Spiridons' secret of invisibility.
Another Thal spaceship crash-lands in the jungle, and the survivors bring news that somewhere on Spiridon there is an army of ten thousand Daleks. Jo meanwhile meets a friendly Spiridon named Wester, who cures a deadly fungus disease that she has contracted.
It transpires that the Daleks' army is frozen in suspended animation in a cavern below their base. The Doctor, with the help of the Thals, explodes a bomb in the cavern wall and thereby causes one of the planet's natural ice volcanoes to erupt, entombing the army in a torrent of liquid ice.
The newly-arrived Dalek Supreme and his aides are left stranded on Spiridon as the Thals steal their ship and the Doctor and Jo depart in the TARDIS.

这次，阴谋家贝洛福（特利·萨瓦拉斯 Telly Savalas 饰）在瑞士山区建立一个疗养院，表面上这是一个普通的高级疗养院，风景秀丽、服务一流，但实际上却是贝洛福进行的一项旨在控制全球的计划的重要基地。在这个疗养院里，贝洛福开发出一种新型病毒，他企图将病毒注射到来这里疗养的女患者身上，然后通过她们传播到世界各地，达到掌握世界主权的目的。贝洛福的阴谋行动引起了英国情报部门的注意，于是007（乔治·拉扎贝 George Lazenby 饰）奉命出动。邦德乔装打扮成家谱学的专家混进了这座疗养院，他必须及时查处贝洛福的阴谋，并阻止他！