動物たちの中で、唯一水中に住む種族がサメだ。彼らは日に日に海が汚れていくことに気づいていたが、そのうちなんとかなるだろうと思っていた。しかし、海底都市の機能にも支障が現れ始めた時には、事態はかなり深刻になっていた。不安になって地上に出てみると、他の動物たちが移民船団を建設していた。彼らに合流することを決意したが、多くの水を必要とするサメたちは、急いで水の生成と濾過のための巨大な装置を開発し、遅れて移民船団を完成させたのだった。

Of all the animals, sharks are the only species that live in the water. They had noticed that the ocean was becoming polluted day by day, but they thought they would be able to manage it in time. However, the situation became much more serious when the undersea city began to show signs of functioning problems. Anxious, they went above ground and found that other animals were building a fleet of immigrant ships. Determined to join them, the sharks, needing lots of water, hurriedly developed a huge apparatus for water generation and filtration, and belatedly completed the immigrant fleet.