The Laroches have just moved into a spooky old mansion when the parents go on vacation, leaving 11-year-old Victor alone at home with his big sisters Cora and Louise. Exploring the rooms of the old house, Victor finds a little stuffed crocodile with empty eye sockets among the dusty packing boxes and ancient African masks. Suddenly, standing wide-eyed before a big mirror, Victor freezes in fright: A dark silhouette darts through the house behind him. A burglar? A ghost? Victor starts looking for the intruder in panic. In the Forbidden Room, he finds the diary of Cecilia, a girl that died in the house many years ago in mysterious circumstances. Victor pages through the book in fascination, following Cecilia’s mysterious clues through the mansion.