A young husband and wife, Alice and Robert, attend an extravagant party given by one of Robert's wealthy clients, Ridgeway. At the party Alice accepts a gift of a pearl necklace from her wealthy host and in consequence has a misunderstanding with Robert. All of Ridgeway's guests are invited on a yachting cruise during which Ridgeway is attentive to Alice, while Robert flirts with a wealthy widow. One night, Alice dreams that, when Ridgeway tries to attack her, she jumps into the sea and is carried to Neptune's court. There a festival is held in her honor, and she is shown the most beautiful of the sea's sirens. When a witch discovers that the pearl necklace has made a mark of vanity on Alice's neck, Neptune orders her from the deep. Alice awakens, returns the necklace to Ridgeway, and is reconciled with Robert.