The Cat in the Hat, Sally, and Dick take an undersea voyage aboard the S.S. Undersea Glubber Traveling down from the Sunny Zone to the Dark Zone to the Trench at the bottom, Captain Cat and his crew get up close and personal with the different life forms found at each level of the ocean. Along the way, they meet sharks, jellyfish, dolphins, manatees, whales, and sea cucumbers, to name just a few