Spring. Cherry blossoms dance at Private Arcadia Academy.

In this academy, known as one of the most prestigious schools, there are seven students who are particularly famous.

Pride, Greed, Envy, Wrath, Lust, Gluttony, and Sloth—.

Embodying their respective sins, they are a headache for the teachers and are secretly called the "Seven Sins" by the other students.

An April morning carries a slightly special air for everyone. The scent of new uniforms, the atmosphere of an unfamiliar classroom, and the spring breeze blowing through the hallways—all of these force the realization that a new school year has begun.

In front of the gates of Private Arcadia Academy, cherry blossom petals dance as if sliding across the cobblestones, adding a momentary brilliance to the students' feet.

First day of the new semester.