Algy, Bulldog Drummond's right-hand-man, is getting married. Bulldog attends; on the way home, in the fog, he enters the (apparently deserted) mansion of Prince Achmed in search of a phone. He finds none, but he does find a body - which disappears when he summons a bobby. Bodies keep disappearing as Drummond keeps summoning the authorities, particularly his long-suffering upstairs neighbor, Captain Nielsen; the ever faithful Algy also finds his wedding night disrupted by, among other things, some emergency code-breaking. And of course, there's a beautiful woman in this case, Gwen, who turns out to be the daughter of the dead man who started all this.