An Arizona boy named Johann visits his grandparents who live along the Chesapeake Bay. Johann and his grandfather- a brilliant scientist known in the family as Grumpa-go canoeing on the Bay. Johann is thrilled to see rays, menhaden, striped bass, jellyfish, kingfishers, and other interesting things. Tired after his long flight, the boy falls asleep in the canoe but Grumpa keeps paddling. Along the Calvert Cliff, the entrance to a cave seems to be...