S2E03 Butterfly of Farewell!/Plot

Rin Matsuoka changes dorm rooms, moving in with Sosuke Yamazaki. Aiichiro Nitori also gains a new roommate -- Momotaro Mikoshiba.

Meanwhile, Iwatobi High School holds a culture festival where the swim club participates in a club-versus-club land-based relay race, hoping to draw attention to their club in the process. The relay starts with Haruka Nanase being the first runner. Although his form is perfect, he lacks speed. Despite being in last pole position, he makes a perfect pass to Makoto Tachibana, who manages to catch up to the others. Nagisa Hazuki fumbles his pass which loses them time, but Rei Ryugazaki is able to save the relay, obtaining victory. Still, there are no further Iwatobi Swimming Club recruits.

The group turns their attention towards practicing for the upcoming prefectural tournament. Makoto says that since it is his last year, he is going to enter freestyle, surprising Haruka. Nagisa comments that he might enter butterfly. Rei worries whether it is okay that he swims only swim butterfly. His worries increase when one of the upperclassmen from the track team happens to ask if he would like to return to track. Then Haruka asks Gou Matsuoka about Sosuke. When Gou suggests that Haruka may be scouted just as Sosuke has been, Haruka replies, "I swim because I want to." Witnessing this, Rei questions his own reasons for swimming. From that day on, Rei rejects all of Nagisa's efforts to hang out after school, saying that he has errands to run.

Nagisa becomes concerned and shares this with the others. Goro Sasabe suggests that maybe Rei is lovesick. Gou approaches Rei with a stack of books about relationships, but upon finding out that Gou thinks that he is love, he denies it and laughs uncontrollably, saying that there is no way he would be taken in by something "as illogical as love." Under Gou's incessant questioning, however, Rei becomes flustered before fleeing the scene, using his "minor business" as an excuse.

Gou spots Rei with a guy and thinks they are dating. She brings the team to see the guy and Makoto recognizes him as Tadanori Sera, captain of the track team. They begin speculating that Rei might, indeed, be planning to quit the swim club and call an emergency swim club meeting. Once everyone is there, however, no one can get the words out. Just as Rei is preparing to leave, Nagisa grabs onto Rei's leg and begs him not to quit the club. The rest also try to convince Rei not to quit. Rei reveals that he has no intention of quitting, yet leaves on another errand. The group follows and ends up at Samezuka Academy's natatorium where they learn that Rei has been secretly taking swimming lessons from Rin in order to learn other styles besides butterfly.

Back at Iwatobi, Rei shows off his new skills, but the group is unable to muster up amazement since they already knew Rei's secret. They decide against telling Rei the truth. Still, Haruka tells him that he has worked hard, leading Rei to smile and get teary-eyed.