Natsuo is still reeling from the sudden upheaval in his home. Living together with Hina, the teacher he’s in love with and her sister Rui, the stranger he had a one night stand with, has left him dazed. Natsuo tries to snap himself out of flashbacks of his steamy night with Rui as he looks at her from across the kitchen. Suddenly, Hina comes straight out of the bath with a towel barely covering her breasts, seemingly unaware of the horrified stares of her new family. She even uses part of the towel to pat dry her hair and the edge flutters dangerously, moments away from revealing a nipple. Hina all of a sudden realizes she’s no longer in a house with just women and shrieks, retreating back into the bathroom. This was the start of Natsuo’s difficult time living with his first love.

Natsuo accidentally peeps on Rui in the bathtub, her nipples barely submerged in the water, and he quickly slams the door shut. He intends to make a speedy departure but Rui calls to him to come in. Natsuo argues that even as siblings, it’s weird for them to be in the bath together and Rui very matter-of-factly says “You’ve already seen everything anyway” as if annoyed with his weak retort. Her insistence makes him wonder if she is, in fact, inviting him for illicit activities to the point where he imagines her naked body in front of him, begging him for one more time together. He can’t help the lecherous smile that forms on his face but quickly snaps himself out of it when Rui mentions wanting to discuss something important.

Momo is rumored to be a sleazy, moral-less girl so most students except Rui stay away from her. Even though some of the rumors do have merit, like Momo having had a lot of boyfriends, Rui also learns Momo is incredibly sincere and not afraid to try to connect with others no matter how many times she’s been burned. Rui aids Momo in reaching out to Natsuo after she develops a crush on him.

This scene has Momo and Natsuo together after Momo has confessed and asked Natsuo to come to her room. It’s clear she intends to sleep with him and Natsuo tries to persuade himself that this will be good for both of them. He wants desperately to get his beloved Sensei (Hina) out of his mind and he figures a girl that has had numerous guys won’t mind meaningless sex. Momo pushes Natsuo down on her bed and starts taking her clothes off. In the middle of this, Natsuo gets a text and Momo urges him to check it. Hearing that it’s Rui asking about dinner, Momo mentions how she usually eats alone because her family doesn’t really get along. She quickly tries to get things going again, not wanting Natsuo to feel sorry for her and lose his drive. Now under him, Momo asks him to undo her buttons and her large boobs are immediately visible as she’s not wearing a bra. Something else that becomes noticeable is the scars on her wrist that Natsuo can’t take his eyes off. This puts an end to their activities as Natsuo realizes she’s more sensitive than she appears. This is definitely the most explicit and sad scene of the whole anime.

Natsuo decides late at night to go to his oldest step-sister’s room but before he can knock, he hears Hina gasp. Natsuo peers through the cracked door and sees Hina under a blanket with her back arched, touching herself. She clenches the sheets with her free hand and takes in shallow breathes, her face flushed. Natsuo watches her, transfixed. In a husky voice, she calls out Shuu (her boyfriend’s) name and Natsuo drops his book, putting an end to Hina’s self-pleasuring.

In another ‘steamy but saddening’ scene, Natsuo goes to confront Hina about her affair with a married man. Backed into a corner, she haughtily tells him he’s too much of a child to understand and shouldn’t meddle in adults’ doings. Natsuo kisses her, stopping her from saying anything more. She momentarily closes her eyes before pushing him away and slapping him. Natsuo instantly deflates and apologizes. Wanting to ruin Natsuo’s fantasy of making love to her, Hina pulls him in for an aggressive kiss. He eagerly reciprocates until she forces him onto her bed. He gasps and Hina unceremoniously rips his shirt open and pins his arms. Natsuo lays motionless, shocked by Hina’s unusually cold behavior. Seeing his lack of resolve, she chides him for still being too much of a child to follow through. She seems so in control, almost dangerous, and Natsuo is heartbroken.