Coney island vendors Baltimore Clark (Bill Boyd), Dutch Herman (Robert Armstrong) and Skeets O'Reilly (James Gleason) spend their off-hours (and some of their on-hours) carrying on a friendly rivalry for the affections of the pert Sally (Ginger Rogers). But when America enters WW1, our three heroes leave Sally behind and join the Navy. Before long, Baltimore, Dutch and Skeets find themselves smack in the middle of an ongoing conflict between the German U-boat fleet and a shadowy "mystery" ship. Naturally, the boys are crewmen on the aforementioned mystery vessel, which is used as a decoy to bring the enemy out into the open. Despite this tense situation, the film spends a goodly amount of time showing the three protagonists cheerfully cheating on Sally with fetching foreign damsels in other ports of call.