Humphrey Proudfoot is a class-conscious solicitor whose daughter falls in love with the son of a disreputable greyhound owner Alfred Gilbey who lives in the same apartment building. After Humphrey fails to convince his daughter not to marry the young Gilbey, he decides to employ a private investigator in order to dig up some dirt on the womanizing gambler. But his sneaky shenanigans backfire when Gilbey turns the tables and discovers Proudfoot's first love Emily. When Emily turns up at the same time as Gilbey's mistress Gloria, the two men suddenly find themselves on the same side as they struggle to keep their two women away from their wives in this classic comic farce.