Three years after the events of "Pretty Rhythm: Aurora Dream," Aira, Mion, and Rizumu have grown up and tutor a new group of aspiring idols: Karin, Reina, Mia, and Ayami, who form the Prizmmy☆. Teenage girls from Korea, named Somin, Shiyoon, Haein, Chaekyung, and Jae Eun (who are the PURETTY), appear as a rival group.

Naru Ayase is an 8th grader who can see the colors of music when she listens to it. For Naru, who is extremely good at decorating, becoming the owner of a shop like Dear Crown was her dream. One day, she finds out that the manager of a newly-opened shop is recruiting middle school girls who can do Prism Dance, and immediately applies. Naru begins to Prism Dance at the audition, and an aura she's never experienced spreads out in front of her. At that moment, a mysterious girl named Rinne asks her if she can see "rainbow music." (Source: ANN)

Matsutarou Sakaguchi is a giant roughneck man with strength far beyond ordinary people. He never uttered words like "work hard," "strive," and "dream" like the typical shounen manga protagonist. However, he is stronger than anyone and peerless in sumo wrestling. His greatest weakness is his own carefree personality. He grows into a full-fledged sumo wrestler. (Source: ANN)

Former ace runner of Sendai Josei High School, Kakeru Kurahara is chased away from a convenience store for shoplifting. Shaking off his pursuer, he runs into Haiji Kiyose, another student from his university. Haiji is impressed by Kakeru's agility and persuades him to live in Chikusei-sou, the run-down apartment where Haiji resides along with eight other students. Having lost his entire apartment deposit at a mahjong parlor, Kakeru accepts the offer reluctantly. However, Haiji reveals a secret during Kakeru's welcoming party: the apartment is actually the dormitory of the Kansei University Track Club. He unveils his ultimate goal of participating in the Hakone Ekiden—one of the most prominent university marathon relay races in Japan. Unfortunately, all the residents apart from Haiji and Kakeru are complete running novices. Worse still, none of the inhabitants are even remotely interested in being involved with Haiji's ridiculous plan! With only months before the deadline, will the fourth-year student be able to convince them otherwise and realize his elusive dream of running in the Hakone Ekiden? [Written by MAL Rewrite]