In 2500 A.D., because the polar glaciers melted and the earth became a sea, people could only live on water, so islands on the sea were formed. It has also become a rarity. Seawalker Marina is a mutant with gills and webs. On this day, when Marina exchanged a pot of soil for fresh water and tomato seedlings on the floating island of Ator, the secret of his body was found and he was imprisoned as a monster and was about to be executed. At the same time, because the pirate smoker knew that Enola had a land map tattooed on his back, he led his men to attack Ator and hunt down Enola. Resident Helen is Enola's adoptive mother. They failed to catch up with the fleeing lifeboat, but happened to meet Seawalker Marina. The three also confirmed the truth of the map behind Enola during the escape, and the withdrawn Marina gradually became friendly. Under the continuous pursuit of pirates, Enola was caught by pirates. Finally, Marina destroyed the pirate's base camp with her extraordinary wit and bravery, and found the land