After the Great Flood ended the War of Ten Billion Deaths, the Earth was buried in torrents of water. Oceans stretched as far as the eye could see. Billions of helpless people drowned, landmasses disappeared and cities submerged beneath the waves. The year was 3045, and a lone colony of survivors built a grand city from the ruins of their once-prosperous metropolis on an island in the middle of the vast ocean. This city was Nautilonia, standing alone amongst great stretches of water, a sea in all directions, a sea of unknown dangers of the deep, a sea of monsters. A fearful fisherman named Enzo, with the burden of his father's grand legacy on his shoulders, must convince Nautilonia that the city is in grave danger as an enormous threat lurks in the depths off its shores.