Set in a steamy Glasgow of the early 1950s, the film focuses on the existential crisis of Joe, a rootless young drifter who finds work on a barge owned by the down-to-earth Les and his enigmatic wife Ella. One afternoon Joe and Les happen upon a corpse of a young woman floating in the water. As the police investigate the case and a suspect is arrested, it becomes evident that Joe knows more about the drowned woman than he is letting on. Meanwhile, against the background of this mysterious death and the 'murder' investigation, Joe and Ella embark on an intimate and passionate affair.