The setting is modern-day Japan, Harusaki High School. In the spring of his second year, the protagonist transfers to Harusaki High from his previous school. The protagonist once possessed enough strength to be called the "strongest," but he hides that fact. He wishes to avoid conflict and live a normal high school life. He hates injustice and cannot ignore someone in trouble. Though he usually spends his days peacefully, he will not hesitate to stand up to protect those dear to him. On his first day as a transfer student, the protagonist meets the central figures of Harusaki High: Rinto Kamishiro, Iori Sumeragi, and Rei Mikage. Rinto takes an interest in the protagonist's calm demeanor and hidden strength. Iori notices the protagonist's kindness and character. Rei is drawn to the protagonist's natural, unguarded self and tries to get closer. The protagonist begins his new school life while keeping his past hidden.

Teacher "Starting today, a new classmate will be joining this class."