Hibiki and Kanade decide to take Eren to the beach, where the Lucky Spoon is holding a sand art contest. After some confusion over what to build, they inadvertently end up with Hummy as their model. As Eren tries to understand the meaning of friendship, she has trouble getting round to calling Hibiki and Kanade by their names. When Eren accidentally ruins the Sand Hummy they built, Hibiki and Kanade reassure her that it won't ruin their friendship. Just as they finish rebuilding their Sand Hummy, Trio the Minor appear and transform it into a Negatone. Defending the other competitors' sand arts, Eren honours her friendship and works with the other girls to beat the Negatone. Despite not winning the contest, Eren admits she had fun.
響たちは、エレンを誘って海に出かけることになった。そして、加音町でサンドアートコンテストが開催されるという。3人で優勝を目指そうと張り切る響。しかし、エレンはまだ響たちに気を使っていた。
