Shortly before 5 December, St. Nicholas mysteriously disappears from the castle. The Club helpers don't understand and are worried. St. Nicholas reappears moments later, but he behaves strangely and says unkind things. What happened to him? And why was that Toys Doctor at the castle? Mees and his neighbor Katja discover what is wrong with St. Nicholas and what is the secret of the strange Toys Doctor. St. Nicholas' eve is at risk and they need as quickly as possible to warn the helpers of The Club. Will the Club, Mees, and Katja succeed in time to unmask the Toy Doctor? Can St. Nicholas' eve this year still going through?