Event Year: 2018

After a cutthroat battle with Kohei Imamura, a handsome otaku from school, Iori ends up joining the Peek-a-Boo diving club. Iori arrives home worn out from the day, but perks up when he hears about a party with a women's college. However, his cousin Nanaka won't allow him to stay out three nights in a row, so Iori tries to show her he's an independent man to get her to let him go.

When Iori Kitahara heads off to college, he decides to live at his uncle's dive shop in Izu. Iori is looking forward to experiencing college life, but ends up running into a group of tough guys playing strip rock-paper-scissors. Iori gets dragged into the diving club's crazy shenanigans and ends up spending his first day in college wearing nothing but a pair of underwear.

For the last half of their trip, the Peek-A-Boo members arrive in Miyakojima. Everyone goes for a serious dive into the majestic sea with the exception of Iori, who couldn't obtain his license. Everything is magical with the stunning coral reef, colorful fishes and sea turtles, until the members engage in PaB-style Otori (a drinking custom of Miyakojima), which turns things into a living hell…

"You might be the only one who can't pass the license test," Nanaka says to Iori, pointing out what he's bad at. To avoid being made fun of by Kohei and Nanaka, he practices secretly. Yet, while practice, all he thinks of is how to poison them at dinner. He avoids being pairs with Kohei and Aina and gets Chisa to promise to help him with practice. But, these interactions cause misunderstandings…