In Cinnamoroll's origin story, a white dog flew down from the skies one day and was discovered by a female Cafe Cinnamon worker. The "I.Cinnamoroll" brand depicts an alternate world that poses a what-if question: What if Cinnamoroll had not met the Cafe Cinnamon worker on that fateful day? The "I" in the title stands for both the English first-person pronoun "I" and the Japanese word "ai" (love), and it represents the brand's theme of taking care of one's own body and mind.

From a young age, Kurumi Mirai has aspired to become a magician. Driven by her ambition, she has spent her childhood preparing to join the prestigious Rettoran Academy of Magic. Although Kurumi excels in the selection exam, her dream is crushed when she is not chosen for the elite magic class. Admitted to the standard class at the academy instead, Kurumi soon befriends Maki Kumiiru, her new roommate; and Yuzu Edel, another girl unhappy with her placement. However, to everyone's surprise, their homeroom teacher, Minami Suzuki, promises to teach the class magic anyway. Although skeptical at first, the girls start to believe that this may be their second chance at realizing their dreams and becoming wonderful magicians.

Following the success of Shiny Colors' first concert, Mano Sakuragi and her friends continue to face new challenges. After Straylight, a new unit of 283 Production, makes its debut concert, the members of the units are temporarily shuffled into new groups to prepare for a Halloween event to help them grow individually as idols. While Mano struggles to express her ideas, her fellow unit member Hiori Kazano feels left out by her new comrades' talent. At the same time, Fuyuko Mayuzumi, who has bitterly failed to become Straylight's center, proves completely unable to show her real personality, jeopardizing the entire project in the process. Shiny Colors' producer will have to find a way for Fuyuko to break out of her shell if he wants to see his idol units illuminate the world once more.

College student Tokiwa gets invited to a mixer by his female classmate Suo. But when he arrives with his friends, they're greeted by three dazzlingly handsome men?!