Part ThreeSeries Episode Number: 400
World Premiere: Sat 3 May 1975 - 5:50pm BST [BBC One] (United Kingdom)
First Broadcast: Fri 21 Mar 1980 - 5:30pm CST [WTTW 11 Chicago]
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.