Heart is the source of good or evil thoughts

About a week later, Kiyotaka listens in on a group of boys in the classroom. Ike and Yamauchi had arrived early and are excited to begin swimming later that day in order to see the girls in their swimsuits. Ike and Yamauchi talk about a plan that they've set up in conjunction with another student Hideo Sotomura to record and rank the cup sizes of the breasts of the girls in the class. Ike suddenly invites Kiyotaka to join them in placing bets on who has the largest breasts in the class. He decides to join in with them in order to get closer to his classmates and attempt to make friends.

After lunch, the swimming class begins, but some of the girls of the class foil Ike and Yamauchi's plan to rank their ****** sizes because they are nervous around aggressive boys. Horikita shows up and banters with Kiyotaka for a bit. She notices Kiyotaka's fit body and asks if he works out at all, to which he denies, stating that it is due to genetics. Kushida shows up and tries to start speaking with Horikita, but is coldly rejected. The teacher starts the swimming class and eventually instructs the class to compete with each other in a 50m freestyle separated by gender.

The girls swim first, conducting two races. Horikita comes in second overall, with Kushida coming in fourth, and a girl named Kayano Onodera taking first place. After they are done swimming, Horikita goes over and talks to Kiyotaka, who expresses his interest to just not be the last place. The boys have three races that would be decided with a final, with Kiyotaka taking 10th place, Sudō taking 2nd place, Kōenji taking first, and Hirata taking 3rd. After the conclusion of the races, Kushida goes up to Kiyotaka to compliment him on his fit body, to which he again attributes to genetics, similar to what he had just told Horikita.