31 January 1976
Tony Beckley (Harrison Chase) John Challis (Scorby) Mark Jones (Arnold Keeler) [1-4], Hubert Rees (John Stevenson) [1-2], John Gleeson (Charles Winlett) [1-2], Michael McStay (Derek Moberley) [1-2], Kenneth Gilbert (Richard Dunbar) [1-4], Michael Barrington (Sir Colin Thackeray) [1, 3-6], Seymour Green (Hargreaves) [1, 3-5], Sylvia Coleridge (Amelia Ducat) [3-5], David Masterman (Guard Leader) [3-4], Ian Fairbairn (Doctor Chester) , Alan Chuntz (Chauffeur) , Harry Fielder (Guard) *, John Acheson (Major Beresford) [5-6], Ray Barron (Sergeant Henderson) [5-6], Mark Jones (The Krynoid’s Voice) 
|Written by||Robert Banks Stewart|
|Directed by||Douglas Camfield|
|Produced by||Philip Hinchcliffe|
An Antarctic expedition unearths two pods which The Doctor recognises as Krynoids. Once germinated, the pods will infect humans, turning them into giant carnivorous plants which will quickly overrun the world. The Doctor and Sarah Jane manage to destroy one Krynoid, but the other is stolen by an insane botanist named Harrison Chase, who intends to use the alien entity to help plants take over the world.