"That day, Ryo and I spent the night together." Ever since they were young, neighbors Hana and Ryo were like brother and sister. Now an adult, Hana still thinks about him. But, on that day five years ago, Ryo slept with Hana while thinking of her sister Yuika. Ryo and Hana end up doing it again after drinks one night. She knows she shouldn't, and she wants to stop... but she just can't!