Hiromi is a soft-spoken girl who loves to paint, and she also happens to be Yuusuke's one and only best friend. Everything was going well with both of their lives, until Hiromi's dad, Rintarou proposed to Yuusuke's mother, Miwa. Things went downhill after that and before they knew it, Hiromi is now an Asahina and every brother seems to be in love with her.