This taut thriller is based on a stage play, and wisely is not opened out too much: after some initial scene setting, the action is concentrated in one apartment and the street immediately outside.
Two con men (Richard Crenna and Jack Weston, both giving beautifully-nuanced performances) reluctantly assist the murderous Harry Roat (Alan Arkin) in his attempt to recover a stash of heroin hidden in a china doll which they believe is in the possession of a blind woman (Audrey Hepburn). The attempts to trick and then terrorise her into giving up the doll, and the distrust between the criminals, give rise to the twists and turns in the plot. It all ends in a tension-filled sequence, much of which takes place in pitch darkness.
Hepburn gives a terrific performance as a frightened woman driven to the ends of her ingenuity, strength and courage, and Arkin is as threatening when restrained as he is when enraged.
According to the box, this 12-certificate DVD "Contains moderate violence and threat". Piffle. Watch it with the lights out, and it will make Psycho look like the Magic Roundabout.