Prizmmy and Puretty attend a live filming of Magical Mion for their self-research report assigned as summer homework. Because most of the cast are unable to arrive on time, Prizmmy is cast as the villains, while Puretty is cast as the victims. The episode is finished early, and Mion suggests Puretty perform a Prism Show to fill time. Throughout this, Hye-in asks Yun-su about the Symphonia Series and learns it leads up to a Prism Act called the Grateful Symphonia.