Yuta has always been pushed around by his unreadable childhood friend, Ran Himeno. One day she suddenly says she has a boyfriend and asks Yuta to be her sex-practice partner. He has feelings for her and cannot bring himself to refuse, but Ran insists that kissing is reserved for someone she truly loves. As the practice continues, her blank expression gives way to erotic moans and visible pleasure, and Yuta can no longer hide how he feels.