Part One
Series Episode Number: 458World Premiere: Sat 1 Oct 1977 - 6:20pm BST [BBC One] (United Kingdom)
First Broadcast: Tue 10 Jun 1980 - 5:30pm CDT [WTTW 11 Chicago]
Running Time: 23 minutes 9 seconds
8.60 Million (UK)
Chart Position: 40 () (UK)
Recorded on Mon 11 Apr 1977 in TC6
An alien virus infects the human crew of a refuelling station on Titan, one of the moons of Saturn. The Doctor is also infected and becomes possessed by the will of the Nucleus.
| Characters include uncredited | ||
|---|---|---|
| Doctor Who |  | Tom Baker |
| Leela |  | Louise Jameson |
| Lowe |  | Michael Sheard |
| Safran |  | Brian Grellis |
| Meeker |  | Edmund Pegge |
| Silvey |  | Jay Neill |
| Crewman |  | Anthony Rowlands |
| Nucleus Voice |  | John Leeson |
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