One Valentine's Day , a girl visited Ryo Mizuhara's house. Her name is Masuda Nishimorika. She takes out the ring with a pack of chocolate and forcibly puts it on Ryo's finger. With the word that it will explode if you try to remove it forcibly. Nishimorika further says that he is Ryo's wife. In this way, Ryo's turbulent marriage partner selection began.