Investigating mysterious power failures and a death at an underground research centre, The Doctor discovers a colony of Silurians - prehistoric, intelligent reptiles who went into hibernation before man evolved. But now they have woken up, and they are prepared to wipe out mankind with a killer plague to get their planet back.
Jon Pertwee
The Doctor
Caroline John
Liz Shaw
Nicholas Courtney
Brigadier Lethbridge-Stewart
Fulton Mackay
Dr. Quinn
Norman Jones
Major Baker
Peter Miles
Dr. Lawrence
Thomasine Heiner
Miss Dawson
John Newman
Spencer
