Part Three
Series Episode Number: 400World Premiere: Sat 3 May 1975 - 5:50pm BST [BBC One] (United Kingdom)
Running Time: 24 minutes 32 seconds
8.90 Million (UK)
Chart Position: 25 () (UK)
Recorded on Tue 17 Dec 1974 in TC3
The Cybermen who are intent on destroying Voga. The Doctor and two of the Nerva crew become walking bombs which they Cybermen will detonate once they reach their target.