Searchlight Doyle, lightweight boxing champion of the United States Navy, is shanghaied into the fleet of Sainte Cassette, an island republic, as a replacement for a wealthy slacker who must serve his country to receive a $2 million inheritance, a scheme concocted by attorney Gabriel Grabowski. All his shipmates, except Hyacinth Nitouche, assume that he is indeed the wastrel he purports to be. Doyle falls in love with Adrienne, the most beautiful of the captain's daughters, and wins her affections by treating his comrades in her teashop. Admiral O'Brien, grandfather of the man Doyle is impersonating, comes to visit, and mistaking him for a civilian, Doyle throws him overboard and to everybody's surprise is complimented on his vigilance. But his real identity is exposed by some American sailors, and he is suspected of killing young O'Brien; he is cleared of suspicion, however, and is reinstated by the admiral, thereby gaining Adrienne's love.