The Stranger (Colin Baker) arrives on Earth with no memory of who he is or why he's there. However, two men on a secret mission seem to know his identity and the owner of a local bar/club seems to be hiding a secret in an upstairs room. Unsure of whom to trust or even believe, The Stranger must try and unravel the threads of his mysterious past...a past he may not want to remember.

In a top-secret UNIT warehouse Dr Sally Arnold is studying a Nestene energy unit with little success. Until she subjects it to cosmic signals that activate it and it awakens several dormant Autons stored in the facility.

The Devil of Winterborne has only recently been exorcised by P.R.O.B.E. but when the body of it's last victim goes missing and a black magic grimoire goes missing from a local museum, Liz Shaw begins to wonder if the ghosts of the past have actually been laid to rest. As she revisits Winterborne School, Liz becomes convinced that the festering evil is once again attempting to exert it's influence. Liz is forced into an uneasy alliance with the now disgraced former headmaster of the school, Gavin Purcell as she must overcome her own emotions to fight the ancient evil that haunts Winterborne.