Part OneSeries Episode Number: 428
World Premiere: Sat 4 Sep 1976 - 6:12pm BST [BBC One] (United Kingdom)
First Broadcast: Mon 5 May 1980 - 5:30pm CDT [WTTW 11 Chicago]
Running Time: 24 minutes 31 seconds
8.30 Million (UK)Appreciation Index: 58 (UK)
Chart Position: 40 () (UK)
Recorded on Mon 03 May 1976 in TC3
The Doctor and Sarah arrive in Renaissance Italy unaware that they have brought a deadly alien energy force with them.