The next port of call in E-Space is another habitable world. Here the people live in fear of 'the three who rule', who live in a high tower overlooking their village. The rulers demand humans whom their guards select from the village and take to the tower never to be seen again. They also keep the villagers in ignorance although there is a small secret group of scientists who are struggling to rediscover and keep alive the knowledge of electricity and technology.

The three who rule, Queen Camilla, King Zargo and Councillor Aukon, are in fact vampires, the surviving crew of the Hydrax, a spacecraft sucked like the TARDIS into a CVE, who have been vampirised by the Great Vampire, the last of a race exterminated by the Time Lords, who is now asleep underground awaiting his next summons.

The Doctor discovers that the tower is the shell of the original spacecraft and arranges for one of the shuttles to lift off and then to plummet to the ground, staking the awakening Great Vampire through the heart. With their controlling influence removed, Camilla, Zargo and Aukon crumble to dust.

_{Synopsis from Doctor Who: The Fourth Doctor Handbook by David J. Howe, Mark Stammers and Stephen James Walker, reprinted with permission; further reproduction is not permitted. Available from Telos}