* Based on a popular long-running manga series created by Fujiko F. Fujio and published by Kodansha in various of its magazines for children. While trying to decide where to spend three days of their summer vacation, Doraemon suggests Nobita, Shizuka, Suneo, and Takeshi an underwater adventure. While exploring the ocean, they end up discovering a civilisation that has been avoiding contact with the surface nations for several thousand years. Note: Screened as a triple feature with Ninja Hattori-kun: Nin Nin Furusato Daisakusen no Maki and Paman - Birdman ga Yattekita.