When something bad happens at Aunt Til's exposition, the Sinterklaas fest seems to end once and for all. A series of terrible events is set in motion, which treatens to free the evil Dr. Brein and her accomplices.

When Sinterklaas has an accident during the test for his “roof certificate,” he ends up in the hospital. Everyone is terribly worried — everyone except the evil Dr. Brein. She wants to use this opportunity to become Sinterklaas herself and change the holiday forever...