When scientists in the Antarctic uncover a mysterious seed pod, the Doctor is called in to investigate. He soon realises it is extraterrestrial and extremely dangerous. At the same time, however, ruthless millionaire plant-lover Harrison Chase has learned of the find and decides he must have the pod for his collection of rare and beautiful flora. Meanwhile the pod itself harbours intelligent life with sinister plans of its own...
as The Doctor
as Sarah Jane Smith
as Harrison Chase
as Richard Dunbar
as Sir Colin Thackeray
as Amelia Ducat
as Scorby
as Arnold Keeler/Krynoid Voice
as Hargreaves
as Derek Moberley
as John Stevensen
as Charles Winlett
as Doctor Chester
as Major Beresford
as Sergeant Henderson
as Chauffeur
as Guard Leader
as Guard