With Hina breaking up with Shuu and the family back together and humming along nicely at home, Rui is enthusiastically approached by a classmate named Kashiwabara Momo. She asks if Rui will be her friend, insists on first-name-basis, and gives her one of the dozens of plushie dolls she has tied to her bag, which…Yikes!
When Rui’s lunch group sees the doll, one of them promptly tosses it in the bin, warning Rui not to catch Momo’s “flirt bug.” There are all kinds of rumors about her sleeping with one guy after the other; even multiple guys at a time. Rui calmly gets up and retrieves the doll from the trash; rumors or no, it’s up to her whether she hangs out with Momo.
Rui’s decision is to hang out with Momo (who’s already made a doll in Rui’s likeness) after school and try to get the proper measure of her. By Momo’s admission she’s been with a lot of guys (thirty by her count), but never more than one at a time, and always in proper relationships that almost always seem to end badly (including one case where the guy locked her up) Yikes!
While at the bookstore, Rui and Momo happen to bump into Natsuo, whom he’s introduced to Momo as “something like” a friend of Rui’s. Then we see first hand how Momo goes about pursuing a guy: she expresses interest in the books he likes, accepts his offer to lend her one, and is then fully smitten when he draws her close to protect her from an errant biker. And that’s pretty much it: she’s totally into him, and asks Rui if it’s okay to ask him out.
Momo is being courteous to her friend by giving her the opportunity to decline the pairing, in the instance she likes Natsuo that way (Momo doesn’t know their domestic situation). In the moment, Rui simply tells her there’s no problem, but it leaves her uneasy later, no doubt due to feelings related to Natsuo she can’t quite process.
But she said no problem, so Momo goes ahead with her pursuit … and rather aggressively, I might add, presenting him with her LINE ID and a note asking if he’ll go on a date with her later, then incidentally presenting her side-tie panties in a quick spin move. But something comes up, and even if Natsuo used LINE (he doesn’t), that something is more important: Rui suddenly develops a severe fever.
No one else is home, so it’s up to Natsuo to nurse her, which means wiping down her sweaty body (“Younger sister, sick person” is his mantra) and even administering a suppository. (Yikes!) Without trying, the two achieved a much deeper level of intimacy, and there’s no hiding anything…which is likely why Rui (normally very direct) feels comfortable brings up Momo’s crush on him, and her uneasiness about that.
The next day Momo isn’t mad (she’s relieved his lack of LINE, not the fact he didn’t like her, was the reason) and has prepared an extremely elaborate homemade lunch with him. They don’t get through that much of it when Momo invites him to her place, and before Natsuo knows it, he’s in her bedroom making out.
They’re interrupted by a text from Rui saying the rest of the fam will be home late again and asking what he wants for dinner. It would be sweet and comforting, if it didn’t so amplify Natsuo’s self-consciousness about his present situation.
The plot further thickens when Momo tells him she never has dinner with her parents, who are virtually never home, before asking him to unbutton her top. Natsuo steels his resolve: sleeping and going out with Momo will help him get over Sensei.
Then Natsuo notices the scars on Momo’s wrists, essentially ending Natsuo’s advance despite her saying they’re “not recent.” Those scars are the final piece of the Kashiwabara Momo puzzle. The compulsive doll-making, lunch-making, sex, and her scars: they all point towards an emotionally vulnerable and above all desperately lonely young woman.
She’s trying the best she can to exist in this world, perhaps the only way she knows how, by offering all of herself to anyone who will acknowledge her existence. But the world has not been kind to her in return. She assumes Natsuo will be the latest guy to freak out about her scars and leave her alone again, but instead he asks for the location of the nearest grocery store.
He whips her up the one dish in which he has reasonable confidence in making, and while it’s hardly haute cuisine, it’s all in the feelings and intent with which he made it. Natsuo didn’t make her dinner something out of it in return, like many if not all the other people Momo’s ever known. He just wanted her to experience what it was like to eat with someone else, something he realizes he’s taken for granted with his new bigger family.
The meal and sentiment bring Momo to joyful tears, as no one has ever made such a gesture to her. But Natsuo insists he won’t go out with her, because he doesn’t want either of them going out with “people we need to depend on.” He sees in Momo a little of the part of himself that feels desperately lonely and incomplete without Sensei, after all.
Casual sex with Momo wasn’t going solve his problem, any more than it ever solved Momo’s problems—it was only going to be a temporary salve. But a lasting friendship? That just might do the trick.