A strange voice is interrupting TV broadcasts across the capital, and bear-like creatures are raiding factories, stealing equipment and killing guards. The Great Intelligence and his army of Yeti have returned. And there’s only one team that can stop them.
Familiar with their foe, Sir Toby calls on the help of Edward Travers to defeat the menace. But without the Doctor to help them, can the Intelligence ever be stopped?
Rachel and Gilmore find a production plant where Yeti are constructing more Yeti. Rachael notes that the inside of a control sphere has a radio transmitter and no propulsion unit, and that much of the equipment inside the Yetis is outdated.
The monks of Det-Sen believe the Intelligence is the product of "consecutive consciousness," i.e. reincarnation, and is from the far future. The Intelligence later boasts that it is millennia old, has consumed more minds than are on Earth, and has traversed the depths of time and space.