In a world of shapeshifting ravens, Yukiya, a Northern leader's son, is summoned by the Imperial Prince as murder, mysteries and an invasion from an unknown enemy threaten the four noble regions.

At Maigahara Music College Affiliate School Maigahara Senior High, there's a rumor circulating among students: "If you give an amazing performance at the school festival, you get special extra credit." Serina's grades are not very good, so she immediately believes the rumor and decides to form a band.

High roller Yumeko Jabami plans to clean house at Hyakkaou Private Academy, a school where students are evaluated solely on their gambling skills.