Masato finally gets a break from his mom's overbearing energy, then immediately loses the one thing keeping him sane about the whole situation. The beach episode strips away the show's usual gag structure and forces genuine stakes out of pure premise chaos. By the time memory returns, you realize how much the show earned its weird family dynamic.

Masato and his party head to the beach for a well-deserved break, a thank-you from Shirase for all their past efforts. Bright sunshine and clear water make for a perfect day until an accident wipes out Masato's memories, including every memory of Mamako. Released as an unaired thirteenth episode, this OVA mixes action, fantasy, comedy and ecchi fan service in a seaside setting.