Frank and Joe travel to the south of France to help Teen Village International rebuild a deserted town as a center for refugee children. But a local legend of a haunted castle, and its lord who hid a fortune in diamonds within its thick stone walls, stirs up strange noises, spooky lights, and close ...

Frank and Joe travel to the south of France to help Teen Village International rebuild a deserted town as a center for refugee children. But a local legend of a haunted castle, and its lord who hid a fortune in diamonds within its thick stone walls, stirs up strange noises, spooky lights, and close shaves that convince the Hardys someone is trying to sabotage the project.

** AN ANCIENT HIDDEN TREASURE STIRS UP A CUNNING PLOT!**

Teen Village International brings Frank and Joe to the south of France to rebuild a deserted town. The finished project will be a center for refugee children. But word is that the local castle is haunted -- by the centuries-old ghost of its lord, who hid a fortune in diamonds from bandits within its thick stone walls.

Spooky lights, strange noises, and several close shaves convince the Hardys that someone is trying to sabotage the project. A pair of French twins, descendants of the owner, want to save the castle from developers. Every facet of the case leads to a dead end -- and the Hardys are hunting a desperate enemy!