When Grandpa notices a storm rolling in, he calls young Jimmy back into their beach house. To pass the time, Grandpa pulls out an old family heirloom, a journal written by Jimmy's great-great-grandfather when he was just a boy. At first Jimmy feigns interest, but soon he is eagerly exploring the high seas, from New Guinea to Guam, with his adventurous ancestor. In his journeys, Jimmy's great-great-grandfather investigates a volcano, befriends wild monkeys, and proves that he is the world's greatest explorer.
