When a lighthouse keeper reports seeing a ball of light plunging into the sea off Tayborough Sands, UNIT sends Mike Yates to investigate. The last thing he expects to find there is an old friend - with a new face...The Doctor and his companions arrive on a pleasure beach in the 1970's, hoping for time off after their recent adventures. But they do not get to relax for long.
Violent incidents are at an all time high in the area and people are going missing - or else changing into something more than human...
The Doctor soon realizes a sinister presence lurks in the cold seas off Tayborough Sands - a presence with sinister designs upon humanity.
Features Tegan and Turlough