A family film, based on a well-known Dutch story from the Middle Ages. Mariken tells the compelling and poetic story of spirited young girl named Mariken. The orphan Mariken lives in a secluded forest with an eccentric old hermit. One day, she decides to leave her surroundings and sets off for town to buy a new goat. On her adventurous journey into the 'real' world, she finds out about the good and bad sides of people.

Sinterklaas receives a letter from Eefje, who has a special wish. This wish is so difficult that it seems impossible. Meanwhile, Huismeesterpiet falls ill for unknown reasons and his duties are taken over by Rommelpiet. The other Pieten disagree with this because since she took charge, the castle has been a mess. Sinterklaas receives a visit from Willem de Schipper, who comes to apply for a job. But Willem turns out to be the missing piece of the puzzle for Eefje's wish.

Two young boy twins receive a boat of their own by a stroke of luck. It turns out to be very fast and they use their boat to help out their friends.