At the Furuhashi household, Fumino is finished taking a shower and goes to measure her weight. Seeing how much she weighs, she screams aloud in pure shock.
The following day at school, Fumino is visibly bothered by the amount of weight she has gained, but wonders if she has done anything to cause it. Upon entering the classroom, she is greeted by Uruka and Rizu, who offer some snacks to her which she happily accepts. A moment after, however, Fumino realizes that it is because of her eating in-between meals that has caused her weight gain. She notices that both Uruka and Rizu eat a lot without restraint and asks why neither of them have gained any weight. Uruka unabashedly points that what Rizu consumes goes to her chest, causing Rizu to choke while eating, whereas she boasts being the type of person who can eat a lot but never gain any weight, to the annoyance of the other two girls. Nevertheless, Fumino decides to stop eating between meals. Not a second later, Nariyuki enters the classroom and shows the trio some cheese starts that Mizuki had made, offering to share some of it to them, but Fumino reluctantly declines the delicious offer, deciding to study instead of eating with her friends.
Unfortunately for her, on each passing day, Uruka, Rizu and Nariyuki all bring with them some wonderful treats -- pudding, eel udon and a cake, respectively -- which have slowly but surely damaged Fumino's concentration, causing her to think of nothing but food. Five days later at the school library, Fumino continues to wonder why she hasn't lost any weight despite going on a diet. Her thoughts are interrupted by Nariyuki, who asks her if she is listening to him. Fumino then notices that it is just the two of them, with Nariyuki informing her that Rizu and Uruka left a while ago as they had to work and train, respectively. Nariyuki then points out that he has noticed Fumino not looking well recently and asks if she wants to go to the infirmary. Fumino says that she is fine, but Nariyuki adds that since she hasn't been focusing much on her studies, he can't ignore her. Fumino tries to reassure him, but her stomach growls, much to her embarrassment. Nariyuki then learns from her that she has been on a diet recently and thus offers her a piece of candy. Fumino is initially overjoyed at the offer, but eventually pulls herself away, telling Nariyuki to get rid of the candy. Nariyuki comments that she doesn't to have gained any weight at all and that she should still eat enough for herself, but Fumino refuses to listen to him, being negatively overdramatic about her situation. Nariyuki insists that she just eat the candy as she is perfectly thin. Fumino abruptly states that her clothes hide her actual figure, raising her uniform to reveal her stomach and asking him to feel it for himself, rendering Nariyuki dumbfounded. Fumino insists, telling him to hurry up and Nariyuki reluctantly complies, thinking to himself how smooth and soft Fumino's skin feels. She then asks what he thinks, with Nariyuki saying how dangerous it was, stunning Fumino.
After school, Fumino is distressed over Nariyuki's comment about her stomach, although the latter tells her that he meant the situation they were in, but his words fall on deaf ears when they come across a convenient store, with Fumino going inside to buy some snacks. Waiting outside, Nariyuki interrogates Fumino, who has come out of the store with bags filled with food, on what she is doing and reminds her of her supposed diet. She answers that she needs the snacks to help her mind focus when she studies, stating that no matter how much she eats she won't gain any weight. Later that night, Fumino goes to measure her weight and is content with what she sees.