When you were a kid, you used to play around with Rio and Kaito, you always had a crush on Rio while unknown to you, Rio had a crush on Kaito but after he left for 10 years and you resolved to become someone stronger for Rio's sake, Rio has slowly but surely begun to grow feelings for you, unfortunately she has been in denial of them as she used to see you as a little brother, until the day came when a girl from school gave a love letter to you and Rio felt jealousy, that moment combined with the return of Kaito gave her the push to have a moment of think to herself, making her have a realization.