The planned marriage between Premierpiet and Probleempiet is in jeopardy, scholars Hans and Frans Steenstra have been kidnapped, and a rare ruby has been stolen from the Rijksmuseum. The dangerous Dr. Brein is behind all of this. Sinterklaas must intervene and even sends his Pieten on a trip to Switzerland to prevent Dr. Brein's criminal organization from gaining power.

• Family