Logopolis

TV Season 18, Serial 7

Aired: 28 February 1981 - 21 March 1981

Last story of Season 18. Tegan is introduced. Nyssa reappears and joins up. First proper appearance of the Antony Ainley Master. Introduces Logopolis and the concept of Block Transfer Computations, the Cloister Room and its Bell, and the idea of the Watcher. And of course, for the Fourth Doctor, this is the end…but the moment has been prepared for.