The mystery of the secret room

When Boomerang the cat disappears into a tiny gap behind the fireplace at Stone Cottage, Scott, Jack and Emily are amazed to discover a secret room that Aunt Kate never knew existed! But what was the room created for? Inside is very little other than an enormous old chest which Jack is convinced ...

In the cold and foggy Christmas holidays, it doesn't seem as though the Five Find-Outers will have anything exciting to investigate. Then they stumble on a single furnished room in an otherwise deserted house. They try to find out who the house belongs to, but they're not making much progress!