Due to family circumstances, Kondou Makoto is living with his childhood girlfriend Narasawa Yui, and her mother. Although Yui is obviously attracted to him, he remains oblivious and pursues the numerous girls who conveniently cross his path.
Two new girls appear, from a rocket no less, and one of them claims to be Kazuya’s fiancée! Amidst all this, a new enemy makes her presence known, forcing the girls to turn against each other while draining their innocence away.
Hina, otherwise known as Guardian Hearts, is sent to Earth with strict orders not to let anyone find out her identity. However Hina is seen transforming as soon as she lands on Earth by a boy named Kazuya.