Episode TwoSeries Episode Number: 221
World Premiere: Sat 9 Nov 1968 - 5:15pm BST [BBC One] (United Kingdom)
Running Time: 24 minutes 26 seconds
7.10 Million (UK)Appreciation Index: 53 (UK)
Chart Position: 55 () (UK)
Recorded on Fri 27 Sep 1968 in Lime Grove D
Archive State: 16mm t/r
Alistair Gordon Lethbridge-Stewart, now a UN Brigadier, confirms to the Doctor that there is something suspicious occurring at International Electromatics.
Zoe and Isobel's investigation places them in terrible danger, and Jamie tries to save them.