Summary: Yuki demands why Shoma came in her. He explains that he didn't mean to, but Yuki suddenly got tighter when Coach was about to leave (which was when she kissed Coach). Shoma also remarks on how happily Yuki and Coach were bantering, and apologizes, but then brings up what Yuki said about him taking responsibility. Yuki asks Shoma what he would do if she got pregnant, and Shoma vows to work after graduating high school to raise their kid. Distressed at the prospect of all of her sexual exploits with Coach having been for nothing, Yuki instead encourages him to work harder at track and field, earn Coach's recommendation, and go to university.
Shoma offers to take Yuki to the showers, but she wants to go alone. Shoma reiterates what he said about her looking happier when she's with Coach. She runs off, past Himeko who sees Shoma calling after her; Himeko gets the impression that they had quarreled. In Coach's office, Yuki takes the shower room key but is caught by Coach. Coach sees Shoma's cum running down her legs, and springs to action. He pulls out pills from his drawers and drags her to the showers, asking her what the hell she was thinking.
In the shower, Coach pins Yuki against the wall as he fingers her and scoops out all of Shoma's cum. He realizes that she had been having raw sex with Shoma while kissing Coach. Yuki can't handle his rough fingering as he continues to do it. He's surprised by how much is deep inside her, but Yuki tells him that the cum he's now touching is not Shoma's anymore (implying that Coach had reached so deep that it's his own). Yuki takes reluctant pleasure from his fingering. Coach asks her if she wants to give birth to Shoma's kid - she shakes her head. With all of Shoma's cum gone, Coach gives her a birth control suppository and feeds her an oral pill by kissing her. He hugs her.
Later in Coach's office, Yuki is resting her head on his lap (at his request). He's worried about her and wants her to rest more before she goes home. He gives her another pill to take that night to make sure it works. Yuki asks him why he has them; he responds that they come in handy. He begins to stroke her, and she trembles. He comments that it reminds him of last year's freshman tournament. Back then, Yuki hadn't been able to advance to the inter-high school round. He reminisces about how she would never cry during training, and didn't even cry in front of her teammates, but cried alone in a corner later. Yuki ended up crying into Coach's chest about how angry she was with herself, and Coach resolved to make her smile this year. Finally, Shoma caught up with them both. Coach remarks about how he thought Shoma was going to be Yuki's mental support, but Coach ended up catching them almost having sex (in Chapter 1), and he felt betrayed by what Shoma and Yuki had done.
At this point in present time, Yuki is aroused, and blames Coach for making her like that. Suddenly, Kureiso's mom walks into her office and catches them looking each other in the eye. Coach sends Yuki away. Mrs. Kureiso demands to know why Shoma was chosen for the upcoming tournament instead of her son. It turns out that is a frequent donor to the school and had told him to choose Kureiso previously. Coach responds that he doesn't show favoritism and chooses athletes based on their times. Mrs. Kureiso clarifies that she *does* want him to show favoritism. She brings up Coach's past (him being a former national-level athlete before his injury) and threatens to expose his and Yuki's relationship to the PTA if he doesn't send Kureiso instead of Shoma. Coach denies it, but Mrs. Kureiso knows that he'll be fired if it gets out. Yuki hears all of this outside the room and despairs at the thought of Coach leaving the school. Coach says that he can only try to give Kureiso better advising, and Mrs. Kureiso leaves in a huff.
Afterwards, Coach exits and finds Yuki listening outside. She concedes that Kureiso could be on the team instead of Shoma. Coach agrees to replace Kureiso with Shoma but still give Shoma the recommendation. He assures Yuki that Shoma has what it takes. Suddenly, Yuki realizes that Shoma had made the team entirely on his own, and she didn't need to start a sexual relationship with Coach in the first place. Coach asks her if getting betrayed feels sad.