Part ThreeSeries Episode Number: 660
World Premiere: Mon 19 Oct 1987 - 7:36pm BST [BBC One] (United Kingdom)
First Broadcast: Tue 23 Jun 2015 - 8:00pm EDT [Retro TV]
Running Time: 24 minutes 30 seconds
5.00 Million (UK)Appreciation Index: 58 (UK)
Chart Position: 79 () (UK)
Mel and Pex play cat and mouse with the lethal cleaner robots while the Doctor and the surviving Kangs learn all about Kroagnon the Great Architect.