Enid Blyton's The Famous Five #15: Five on a Secret Trail

Camping again! This time the gang of Five have pitched their tent near an old ruined cottage - which looks as though it's been abandoned for years! When Anne hears strange noises at night - coming from the cottage - the others don't believe her . . . Until they see the ghostly lights. All of a sudden camping doesn't seem like quite such a good idea. Is the cottage really haunted, or is there another, just as sinister, explanation?