Leon lives in the most mysterious place on Earth: the deep sea. He is part of an elite group of young fluid divers who can move freely even at depths of 1000 meters. Together with Lucy, an intelligent female octopus, Leon roams the Pacific Ocean in search of raw materials. But then the sea seems to go crazy: dead zones are spreading across the ocean floor, creatures of the deep are fleeing in masses, and panic erupts on land. During a forbidden dive, Leon and Lucy discover a deadly experiment and suddenly find themselves with a powerful corporation as their enemy. Ironically, Carima, a young tourist from above, turns out to be Leon's only ally.