Carmelita Lindsay (Lupe Vélez) believes she's finally going away on a honeymoon, which she has been unable to arrange due to her husband Dennis's constant business deals. Dennis (Charles "Buddy" Rogers) secretly intends to use this ocean voyage to sell advertising to the well-to-do Baldwins (Florence Bates and Harry Holman), with help from his Uncle Matt and Aunt Della (Leon Errol and Elisabeth Risdon).
On the cruise, a quarrel with Carmelita results in Dennis being thrown out of his cabin and into another occupied by Parisian blonde Fifi Russell (Marion Martin). The Baldwins, assuming that Dennis and Fifi are man and wife, insist on arranging a meeting with British nobleman Lord Epping. Mistaken identities multiply thereafter, as Carmelita recruits Uncle Matt to pose as Lord Epping, and they both prevail upon passenger Emily Pepper (ZaSu Pitts) to impersonate Lady Epping. Further complicating matters, Carmelita and Dennis's business rival (Eddie Dunn) make Dennis jealous.
The multiple motives and identities become so scrambled that Uncle Matt is cornered. He desperately sounds an alarm, evacuating the passengers so he can escape in the confusion.