Today's story begins in the office of Dr Christian, the doctor of Rivers End, where Judy is at work. Jack Wilson has got his motor boat all tuned up, and wants Dr Christian to take a little fishing trip with them. The doctor really wants to go, but as Judy already knows, there's never any time that Dr Christian manages to leave the practice, just in case anyone needs his help. Jack and Bud go on the trip without Dr Christian and whilst the men are heading back from their trip, there are some loud cracks of thunder, so they decide to shelter in a nearby cavern...