1950s thriller in which a man whose brother was murdered stumbles by chance upon a clue he believes might be the key to solving the case. It is four years since George Keefe (Tom Chatto) lost his brother, a policeman, to the villainy of a man who was never caught. One day, while flicking through a newspaper, George comes across a picture submitted for a photography competition that jolts him to attention. It appears to have been taken on the day that his brother was murdered, shows the getaway vehicle the criminals used and contains a clear image of a young woman. George teams up with investigative journalist Jon Deering (Donald Houston) to try and locate the young woman. Who is she and what does she know about the death of George's brother?