One day, everyone gathers at Cafe "Hako-bune", where Arashi and Hajime are working, and they discuss about the summer tradition. They end up planning to go to the beach, and Hajime is overjoyed because he will be able to see Arashi in her swim suit. Arashi, Kaya, Yayoi, Kanako are all having fun choosing swimsuits from Master's collection. But Jun, misunderstood as a boy, is having a hard time trying to keep his cover. The following day, they go to the beach in Yamashiro's car. Drawing men's attention, playing with the creatures, each one of them enjoys their summer.
喫茶店「方舟」に皆が集まり、夏の風物詩について語り合っていた。話の流れで海に行くことになり、あらしの水着が拝めると大喜びする一。あらしたち女性陣も、マスターが出してきた水着を前に、喜んだり驚いたりと楽しんでいる様子。その中、一に男と勘違いされている潤は、どうごまかそうかと途方にくれるが…。
