The Daleks draft the Second Doctor into distilling the Human Factor. Once implanted, it will make the Dalek race invincible. Jamie's faith in the Doctor is stretched to the limit as the Doctor appears to be collaborating with the Daleks. The Doctor has a few tricks up his sleeve, but then again so might the Daleks.
Patrick Troughton
as The Doctor
Frazer Hines
as Jamie McCrimmon
Deborah Watling
as Victoria Waterfield
John Bailey
as Edward Waterfield
Marius Goring
as Theodore Maxtible
Brigit Forsyth
as Ruth Maxtible
Geoffrey Colville
as Perry
Griffith Davies
as Kennedy
Alec Ross
as Bob Hall
Windsor Davies
as Toby
Sonny Caldinez
as Kemel
Gary Watson
as Arthur Terrall
