Just before December 5, Sinterklaas mysteriously disappears from the castle. The Club's Pieten don't understand what's going on and become worried. When Sinterklaas reappears a little later, he says unkind things and behaves strangely. What happened to Sinterklaas? And what was that Toy Doctor doing at the castle? It is Mees and his neighbor Katja who discover what is going on with Sinterklaas and what the secret of the peculiar Toy Doctor is. Pakjesavond is in danger, and they must warn the Pieten of the Club van Sinterklaas as soon as possible! Will the Club Pieten and Mees & Katja manage to unmask the Toy Doctor in time? Will they succeed in making sure that Pakjesavond can still go ahead this year?

The Piets are facing a modern problem. Most chimneys have disappeared, and many houses today are protected by alarm systems. The poor Piets are constantly chased by the police whenever they try to deliver presents to the children. One by one, they end up in jail. While Sinterklaas is busy trying to solve the Piets’ dilemma, he is kidnapped by the wicked Dr. Brein and her henchmen, Joris and Boris. Meanwhile, Pieta and Mrs. Dakjes are trying to teach a group of young Piets the skills they need for the job. They are also bothered by Michiel who wants to interview Sinterklaas for the school newspaper. Pakjesavond is approaching fast, and for both the Piets and Sinterklaas, it becomes a race against the clock to find a solution in time and save the holiday...

Ranch 'The Horse Farm' is organizing a big cowboy party. Amika should be the star of the evening, but he hurt his back and does not want to ride. As well as the vet and Amika's favorite stuff won't help. Merel and Oli see only one possibility. They hastily go searching for the magic saddle Sofie. If that will make Amika better, the party might have saved ...