As a woman in a wedding dress flees town in a stolen car, Detective Dixon learns Count de Montaigne's gift to his bride, a valuable necklace, was stolen from his wedding reception. Notorious thief "Lady Jane" is believed responsible for the crime. At a gas station, the mysterious woman meets man-about-town Michael Winslow and drops him off at his yacht club. Reporters assume Michael has secretly married when they find a wedding dress in the woman's suitcase, and inside the club, they are introduced as husband and wife. Using the alias Belinda Hipplewaite, the woman dances with Michael in the moonlight, then flees. Meanwhile, the count, who is really a crook called Jake, arrives in search of the jewel thief and finds his stolen car. As Jake's men chase her, Belinda flees in a boat. Michael's fiance, Muriel Courtney, then arrives and insists on going on his yacht "Belinda," where Michael discovers Belinda asleep. When Michael's friends come aboard and reveal his "marriage," Muriel threatens to sue for breach of promise. Meanwhile, Belinda poses as the yacht's stewardess. When Dixon boards the yacht in search of Lady Jane, Belinda identifies herself as Mrs. Winslow and she and Michael are forced to sleep in the same cabin. As they lie awake, Michael tells Belinda he doesn't love Muriel and proposes, but when he finds the necklace hidden in Belinda's room, he accuses her of stealing it. Dixon then uses the necklace as bait to get Jake on board, and Jake realizes that Muriel, a former moll, is Lady Jane. Jake admits that he was going to marry Belinda, whose real name is Toni Ainsworth, because he believed she had money. In turn, Belinda confesses she was marrying him for the same reason, but fled the reception in order to escape a loveless marriage. After Dixon arrests Jake and Muriel, Michael and his new fiance kiss.