Minna lives with her three sisters in the great sea. Like all mermaids, they only eat human flesh, and every day the three sisters go hunt. But Minna doesn't want to eat people, and one day she decides to go out in search of a friend instead. She comes to a small fishing village and meets a child named Mika. Soon they get close, but when Mika's father doesn't come home after a fishing trip, Minna fears that it's her sisters who caught him. Should she tell her new friend what her family lives by, and that they might be behind her father's disappearance? It's not easy to stop eating people.