In 1940s Brighton, England, the vicious criminal Pinkie Brown (Richard Attenborough) is the leader of his small-time gang. After Brown murders a rival, he finds an alibi through a waitress, Rose (Carol Marsh), whom he promises to marry in return for her corroboration. Despite the police ruling it a suicide, Ida Arnold (Hermione Baddeley), a woman who was with Brown's victim before the murder, continues with her own investigation. Meanwhile,Brown is rapidly losing his grip on the situation.