Hard-hitting 1950s crime drama exploring racism towards immigrants among the London police and public. Sapphire (Yvonne Buckingham), a fair-skinned West Indian immigrant, is discovered murdered. To the police, led by Superintendent Hazard (Nigel Patrick) and Inspector Learoyd (Michael Craig), the case seems clear cut - Sapphire must have been killed by a member of the black community. However, when Sapphire's brother (Earl Cameron) turns up at the police station and Sapphire's true ethnic roots become known, Hazard and Learoyd must face up to the racism of two communities and, quite possibly, their own...