Episode ThreeSeries Episode Number: 176
World Premiere: Sat 14 Oct 1967 - 5:25pm BST [BBC One] (United Kingdom)
Running Time: 23 minutes 55 seconds
7.10 Million (UK)Appreciation Index: 51 (UK)
Chart Position: 51 () (UK)
Recorded on Sat 23 Sep 1967 in Lime Grove D
Archive State: Missing
When a Yeti is captured by the Detsen monks, the Doctor discovers that it is a robot but its control sphere is missing. Elsewhere in the monastery, the sphere is on the move.