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"Some kind of organism that attacks the mind, the intelligence. It's trying to take me over, Leela. It's trying to change me"
|Episode Title||Premiere Date|
The TARDIS picks up a mayday message, but before the Doctor and Leela can fully respond, the police box also passes through the mysterious cloud and the Doctor falls victim to a strange virus. As the situation worsens, his only hope lies in the unlikely combination of the eccentric scientist Professor Marius, and his dog-shaped computer, K9...
The Doctor: Tom Baker
Leela: Louise Jameson
K9 (voice): John Leeson
Lowe: Michael Sheard
Professor Marius: Frederick Jaeger
The Nucleus (voice): John Leeson
Marius' Nurse: Elizabeth Norman
Producer: Graham Williams
Director: Derrick Goodwin
Scriptwriters: Bob Baker and Dave Martin