Office secretary Ann is horrified to find a young neighbour murdered when she returns to her London flat one evening. When the police arrive she realises that she had witnessed what must have been the killer leaving the building just as she was entering, but is unable to make a positive identification. Shortly after, she spots the man working in a shop and runs terrified back to the office, convinced that he has followed her. When her detective boyfriend Mark re-assures her that the killer has in fact been caught, she forgets the incident and remains behind in the empty building to finish off a large batch of work. When she unexpectedly finds the security guard murdered and the front doors locked however, a terrifying nightlong ordeal begins, with her and her would-be killer caught in a deadly game of cat and mouse throughout the building.
WRITTEN BY: Brian Clemens
DIRECTED BY: Shaun O'Riordan
PRODUCED BY: John Sichel
MAIN CAST: Julie Sommars (Ann Rogers), Robert Lang (The Man), Anthony Steel (Mr Burton), Tony Selby (Mark), Ken Jones (Sam), Geoffrey Whitehead (Keston), Annette Woollett (Penny)