Part OneSeries Episode Number: 530
World Premiere: Sat 27 Sep 1980 - 6:16pm BST [BBC One] (United Kingdom)
First Broadcast: Sun 22 Nov 1981 - 11:00pm CST [WTTW 11 Chicago]
Running Time: 24 minutes 43 seconds
5.00 Million (UK)Appreciation Index: 61 (UK)
Chart Position: 105 () (UK)
On Zolfa-Thura, Meglos plans to steal the ancient and powerful Dodecahedron from the neighbouring world of Tigella. But first, the Doctor must be prevented from interfering.