Piet Piraat and his friends make a long journey to Katoekieland. On the way, there appears to be a stranger onboard: Esmeralda, the gypsy girl. Everyone immediately falls in love with her, except for Stien, who does not trust her. One night, Stien discovers Esmeralda's true nature. She wants to get hold of their ship with the help of the magical powers of the Gilded Cup that Steven bought at a flea market. Will Stien be able to warn the other pirates in time?