Iori tries to setup another mixer for his friends, and wants to ask Chisa to introduce her friends so they can all play truth or dare. Nanaka and Azusa also get involved, and they all begin a vicious game of attack and defense! However, Iori doesn't have enough money for their trip. Iori and the gang head to a diving shop to buy diving gear, but find out there's still a lot they don't know.

The Peek-a-Boo members arrive in Okinawa! After checking out their gorgeous vacation home, the group decides to head to the beach. In order to make sure the guys don't try to get naked, they decide to go to a popular beach with lots of visitors, where they have some wild fun on a banana boat. However, Iori loses their banana boat contest and ends up having to sleep in Nanaka and Azusa's room!

"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...

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...