It is London, 1894. Amid the fog, cold and degradation, a gruesome business is being conducted. The bodies of the dead are being stolen from their graves - men, women and children alike - for the sinister purpose of a very mysterious gentleman.

When the Doctor and Sam arrive, they are witness to a horrifying scene in the evil-smelling fog: something rises up from the filthy waters of the Thames and devours a man - a man terrified for his life and on the run from the devil himself...

Teaming up with an old friend, pathologist Professor George Litefoot, the Doctor is determined to get to the bottom of the mystery. Together with Sam, they discover there is a far graver threat facing London than just earthly grave robbers. Deadly alien beings the Doctor has encountered before are at work, and they bring a whole new twist to the word 'bodysnatchers'…

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 realises a sinister presence lurks in the cold seas off Tayborough Sands - a presence with sinister designs on humanity.