Today's Adventure: Wet, Hot, Beaches!.It's time for another important summer ritual, the family trip to Doinaka Beach, but Hinata Aki is uable to accompany the children due to work commitments, leaving Natsumi and Fuyuki without an adult guardian, until Kururu reveals his latest invention, an age manipulation beam that turns Natsumi into a full-grown adult. An unexpected side effect causes Natsumi to utter 'old-man' jokes involuntarily, while Keroro's hidden angle and true reason for infiltrating the beach is revealed—the super-rare 'Dangale' knockoff model kits, offered as a prize for entering the Swimsuit Beauty Stand-Up Comic Competition.