The plot follows a family deciding to spend Christmas in the countryside. They intend to rent a small house but stumble across an old castle. Mistaking two thieves for the owners, they "rent" the abandoned castle. Soon their children, Ivar and Lillan, discover that the castle is haunted. At first, the ghosts seem to be evil, but soon the children (who are intrigued instead of terrified) befriend them. But there is something else in the castle—something even the ghosts are afraid of.
