Finn Haddock, the wealthy inventor of a combination toothpick and mint, takes his wife Hattie, their precocious daughter Mildred, and nephew Sidney on an ocean voyage to Paris for a vacation. On the way, they meet Henry Collins and Bessie Chalmers, who poses as a princess to lure Finn into an affair with her so she can milk him for his wealth. Hattie befriends a divorcée who tries to educate her about the pitfalls of marriage, while Mildred finds various methods of ridding herself of Sidney, such as dumping him down the coal shaft, in addition to trying to keep her father out of mischief with "The Princess." In Paris, Hattie plays the retiring wife and refuses to go out with Finn. Finn goes to a cafe where he gets drunk and hires "The Bottin" to take Hattie out on the town. The Princess meets him at the cafe and persuades Finn to go to an apache nightclub with her, where she cons him into writing her a $50,000 check. While attending the same club with The Bottin, Hattie sees Finn and The Princess together and becomes enraged. After Finn and The Bottin, both drunk, go outside, The Princess tells Hattie that Finn misled her and Hattie relents and gets drunk too. Finn sneaks into the apartment late the next morning, but Hattie wakes up and discovers that The Princess spent the night with her. Mildred intervenes while the adults argue, and knocking The Princess over, takes the check out of her stocking. The Princess leaves with Henry, but not before Finn manages to flip Henry with a wrestling move. Finn and Hattie apologize to one another and are reunited as they hear the cries of Sidney, whom Mildred has kept busy by maliciously putting the fishbowl on his head.