The Iwatobi Swim Club needs one more member before it can participate in relays.  Nagisa has set his sights on his classmate Rei, who is a member of the track team.  Despite Rei's refusal to join, but Nagisa appears intent on recruiting Rei into the swim club.
Ouch.
Aua.
Aïe.
Ahi.
Ai.
Ой-ой.