The Saint's Girl Friday (1953)

A socialite is killed when her car plunges into a river. Meanwhile, the Saint (Louis Hayward) returns to London from New York with his valet, Thomas Gallagher. He learns of the death of his girlfriend. Inspector Teal (Charles Victor) feels his heartburn coming back on because the Saint is back in town. Hayward dodges the tails that Victor has put on him, and goes to talk with Russell Napier, who was the guardian of the girlfriend. He tells him that she had been gambling, so Hayward goes looking for an undercover game. Naomi Chance takes him to one. She is being forced to work as a shill for the River Gang to pay off a gambling debt. Hayward is still trying to find the Boss, and a contact steers him to the Safari Club.

Hayward goes into the back room of the club, and at the appointed time, Gallagher starts a fight in the front room. Now Victor starts to get involved, and his men pick up some of the hoods. He steals some information from the girlfriend of the Boss and sends Gallagher to find the location of the gambling boat. Then he goes to a party thrown by the Ambassador. The Ambassador's son is in trouble with the River Mob, but he tells Hayward he is ready to testify against them. However, he dies that night in an apparent suicide, but Hayward is sure it is murder.

The mob breaks into Hayward's apartment and knocks out Gallagher. When Hayward gets home, they try to kidnap him, but he knocks out the light and turns the table on them. However, they capture Chance and use her to bring in Hayward. The boss of the mob turns out to be an underworld contact that had pretended to be helpful to Hayward.