The Doctor has been to Det-Sen Monastery before, and expects the welcome of a lifetime. But the monastery is a very different place from when the Doctor last came. Fearing an attack at any moment by the legendary Yeti, the monks are prepared to defend themselves, and see the Doctor as a threat.
The Doctor and his friends join forces with Travers, an English explorer out to prove the existence of the elusive abominable snowmen. But they soon discover that these Yeti are not the timid animals that Travers seeks. They are the unstoppable servants of an alien Intelligence.
This novel is based on a Doctor Who story which was originally broadcast from 30 September - 4 November 1967.