The Butterfly of Farewell!.Iwatobi High School holds a culture festival where the Swim Club participates in a land-based relay race against other clubs, though their victory fails to attract new members. As the group preps for the national tournament, Rei worries if it's acceptable that he only swims butterfly. Nagisa becomes concerned when Rei starts going off on "errands" after school, with the others becoming suspicious, especially when they spot Rei speaking with the track team captain. They beg him not to quit the swim team, but are happy to discover that his "errand" is taking lessons from Rin in order to learn the other swim strokes.