Gamu and Choco want to make the next AiPri Festival a success, so they start building a huge sandcastle on the beach. Just as it's almost finished, they go home to get the flag they'll put on top. When they return to the beach with Gumi, they find the sandcastle has been swallowed by the waves and collapsed. Dejected, Gamu and Choco end up fighting. Inori and Aoi perform a live show to cheer up Choco. Meanwhile, Emma appears before Gamu, who has made a wish: "I hope I can build a sandcastle with Choco again." It turns out that Emma was the one who advised him to make the wish. What exactly is her aim...?
