Episode FourSeries Episode Number: 509
World Premiere: Sat 22 Sep 1979 - 6:17pm BST [BBC One] (United Kingdom)
First Broadcast: Fri 29 Jun 2001 - 10:30pm CDT [Prairie Public Television]
Running Time: 26 minutes 5 seconds
14.40 Million (UK)Appreciation Index: 64 (UK)
Chart Position: 27 () (UK)
Recorded on Mon 16 Jul 1979 in Television Centre 1
The Doctor discovers that the Daleks need Davros to break the stalemate in their war with the Movellans, and the Movellans now want the Doctor to fulfil the same purpose for them.