Pinkie Brown (Richard Attenborough) is a small-town hoodlum whose gang runs a protection racket based at Brighton race course. When Pinkie orders the murder of a rival, Fred (Alan Wheatley), the police believe it to be suicide. This doesn't convince Ida Arnold (Hermione Baddeley), who was with Fred just before he died, and she sets out to find the truth. She comes across naive waitress Rose (Carol Marsh), who can prove that Fred was murdered. In an attempt to keep Rose quiet Pinkie marries her. But with his gang beginning to doubt his ability, and his rivals taking over his business, Pinkie starts to become more desperate and violent.