Having been called the "ultimate diving machines," the Northern Elephant Seal is the most sophisticated diving mammal and the largest, most powerful pinneped. Distinguished by the male's elongated, trunk-like nose, it's often seen on beaches from Mexico to Alaska. This film, however, follows the seal into the waters of the Pacific and chronicles, for the first time, its active underwater life. We begin on the beach with the birth of a pup. Through the trial of babyhood and adolescence, we learn just what it takes to become a three-ton seal that can out dive even the great whales.