Norman Pitkin works at Scotland Yard as a car cleaner, but dreams of becoming a policeman as his late father was. The police reject his request to join the force, but later recruit him to work undercover in disguise. He has turned out to be the double twin of a suspected jewel thief, an Italian crime boss in London. In addition to his criminal activities, this man is a ladies' hairdresser.
Norman disguises himself as the suspect and gains entry to his salon. Once inside, after some inevitable mishaps, he manages to find the stolen goods, knock out the suspect, wrap him up in a curtain/wall rug, and bring him to justice.
As a reward, he is offered a permanent position in the police and marries his love, the ex-girlfriend of the man he brought to justice (whom he had rescued earlier in the film when she was attempting to commit suicide by jumping in the river).