A British couple staying at a Spanish villa are put through an ordeal when a mystery man, who speaks only German, holds them hostage.
An underrated episode of this excellent series - tense and claustrophobic, with a palpably queasy atmosphere of unease, imminent doom and implied nastiness.
These films are television plays in the best sense - entirely character driven. They are also subtle, requiring viewers to join a lot of the dots themselves, and often trade on ambiguity. Usually ending on a question mark.
Acting is very good, but it's the 'monsters' who get the most meat - and special mention in this case must go to Ray Smith, who may be familiar to some viewers as the policeman ally of 'Public Eye' Frank Marker - here Smith is outstanding as the intruder. Terrifying, menacing, at times friendly, his intentions never clear, it's a tour de force, and without speaking a word of English.