When Shūsuke gets a report about him failing in all of his subjects, he then realizes that he has to take a follow-up exam or risk having to take summer classes. Believing that she was the cause of Shūsuke's grade for calling him out each night, Mayuka feels guilty and offers to help him study for an upcoming exam. But while they were studying, Nao and Iroha decide to intrude on them. As Mayuka tries to get Shūsuke to study, Nao and Iroha compete to try and catch his attention. After some time later, Iroha presents surprise tickets for everyone to go to a local pool park if he passed, which encourages Shūsuke enough to pass. At the pool, Shūsuke spends most of his time teaching Mayuka how to swim, leaving Nao and Iroha pretty jealous. During that time, Mayuka becomes amorously focused with Shusuke's nipples, having never seen a man naked before. As Nao tries to press Mayuka on her attraction to Shūsuke, he nearly drowns after Iroha forces him on a water slide, but is revived thanks to Mayuka's 'cardiac massage'. Afterwards, Mayuka leaves Shūsuke a large list of BL books to buy while she is on holiday.
繭佳のパシリを続けていた修輔は、勉強不足のため赤点を取ってしまった。
見かねた繭佳は修輔の自宅で勉強を手伝うのだが、当然黙って見過ごす訳にはいかない奈緒、彩葉はその場に同席し、
3人のしたたかなバトルが水面下で繰り広げられるが、彩葉の提案を受けて一同はプールへ行くことに。
Cuando Shūsuke recibe un informe sobre su fracaso en todas sus materias, se da cuenta de que tiene que tomar un examen de seguimiento o arriesgarse a tener que tomar clases de verano. Creyendo que ella era la causa de la calificación de Shūsuke por llamarlo todas las noches, Mayuka se siente culpable y se ofrece a ayudarlo a estudiar para un próximo examen.
茧佳继续差遣着修辅，而修辅学习不足而不及格了。看不过去的茧佳，来到修辅的家中帮他学习，但是，当然奈绪无法视而不见的，因此和彩叶一起对修辅进行了袭击。3人的厉害的战斗在水面下展开了，彩叶建议大家去游泳池。
