Akeno is a beautiful mermaid, whose work is to make sure that all the sea people are keeping their identity secret. Especially the ones living among humans. She is very good fighter and is very skilful sword master. If anyone fails she will send him back to the sea world. But with time Akeno becomes part of Michishio’s class and starts liking and helping him. Akeno’s biggest dream is to find her big brother who has mysteriously disappeared many years ago.