Tristan, Katinka, Kirk, and Petra are a group of orphaned siblings who have been “hired as children” by their former housekeeper, Miss Nelly, and his boyfriend Brian. They have created a happy family and look forward to the best Christmas ever in their new home on Martinsvej. But one day, the Welfare Witch comes knocking. The children’s grandparents have discovered that their daughter is missing, and they want custody of the children. With the law on the grandparents’ side, the kids must use every trick in the book to stay on Martinsvej. Soon, a daring plan begins to take shape - one that just might let them celebrate Christmas with Nelly and Brian after all.