The Predecessor [X] with Elegance with the Missing Item on the Beach.Kominami takes Nariyuki to the beach to fake romantic pictures for her father. The ocean washes away her bikini, so Nariyuki gives her his shirt. Kominami refuses to leave braless and is prevented finding her bikini by nearby swimmers so she clings to Nariyuki, embarrassing him. Nariyuki finds two bikinis and decides to place the second in lost and found, but it is stolen by a dolphin. After Kominami leaves Nariyuki tries to get changed but realises Kominami still has his shirt. He suddenly finds Kirisu hiding topless, as the second lost bikini was hers. Nariyuki tries to lead her to safety but she slips, pressing her breasts against him and breaks his glasses, forcing her to lead him to safety instead. Nariyuki buys a new bikini, but the only type available is a school swimsuit. Nariyuki is spotted by other teachers visiting the beach, forcing Kirisu to hide in case she is spotted in a school swimsuit with Nariyuki...