Episode OneSeries Episode Number: 220
World Premiere: Sat 2 Nov 1968 - 5:15pm BST [BBC One] (United Kingdom)
Running Time: 24 minutes 32 seconds
7.30 Million (UK)Appreciation Index: 55 (UK)
Chart Position: 55 () (UK)
Recorded on Fri 20 Sep 1968 in Lime Grove D
Archive State: Missing
The TARDIS lands in London where the Doctor, Jamie and Zoe agree to help find Isobel Watkins' missing uncle.
Searching for Professor Watkins at his last place of work, a multinational electronics supplier, he meets the company's managing director. He's not what he seems - and possesses alien technology in his office.