Scotland, the near future. Something is smashing oil rigs off the Scottish coast, and UNIT have been called in to investigate. The Brigadier summons the Doctor to Earth to help in the investigation, but it soon becomes clear some kind of alien presence is at work...
Quest roles:
Ian Marter(Harry Sullivan), Nicholas Courtney(Brig. Lethbridge-Stewart), Angus Lennie(Storr), John Levene(Sergeant Benton), John Woodnutt(Seron), Lillias Walker(Sister Lamont), Tony Sibbald(Huckle), Bruce Wightman(Radio Operator), Hugh Martin(Munro), Robert Russell(The Caber), Keith Ashley(Dalek Operator)