Peek a Boo arrives in Okinawa for their trip. Aina looks forward to making happy memories, but her initial happiness is quickly dashed when the men of the group start running around naked, leading her to convince the men to head to a public beach where they have to wear swimming trunks. At the beach, Iori and Kohei decide to ride a banana boat to determine which one of them stays in the men's bedroom with Shinji and Ryujiro...