What reason had anyone in the village to connect the disappearance of the boat, the lost horse, the widow's herring, the cork life jacket, the windowpane, the lost peat, the rusty clock spring, or the strange prints in the earth with McCullem's Cave? Who milked the old lady's cow and left a mysterious note? Since there seemed to be some connection to the cave, Roy determined to find out by exploring there. Inside the dark cave, he found a door. Peering in through a crack, he saw--Read the book and discover the secret of the cave!