Believing that the added pressure will help the Swim Club in their training, Gou continues to make her countdown calender for the upcoming prefectural tournament. Meanwhile, as the guys decide on which events they will each participate in at the tournament, Gou discovers a decades old training regiment of the past Iwatobi Swim Club, and excitedly proposes that they use it and venture to an island for a summer training camp.
Afterwards, the club tries and fails to get Miho to sponsor the trip. Makoto proposes using camping equipment to stay outdoors while resorting to bribing Sasabe to use his squid fishing boat to take them to the island and back. Later, Haruka expresses concern for Makoto since he had a rather scarring experience with the ocean in the past, to which Makoto reassures that he is fine.
On the day of the trip, Sasabe takes the Swim Club to the island where they coincidentally discover the Samezuka Swim Club, along with Rin, training at a special swimming facility on the island. After the guys get settled on the beach they begin their stamina training regiment which involves making three long-distance swimming circuits between the deserted islands of Sukishima, Oshima, and Mizushima. At the end of the first day, the club only manages swimming half of their goal, leaving Rei to feel a bit disappointed for lagging behind.
As they prepare for dinner, Gou heads to a nearby convenience store and briefly runs into Rin who shows some concern for Makoto after Gou explains their training, before returning to his usual stoic self. That night, unable to sleep due to his performance, Rei heads into the ocean to continue training when a sudden storm takes him by surprise. Makoto awakens at that moment and goes looking for Rei, frantically diving to his aid upon hearing Rei's cries for help.