Lo que debería haber sido un día normal de escuela para Kou Kai y su amigo Itsushi Saito se convirtió en el principio de una tragedia... ¿O tal vez fue el final? Observa cómo Kai intenta escapar de la desesperada situación con un remordimiento del pasado como fuente de energía.

What should have been a normal school day for Kou Kai and his friend Itsushi Saito turned out to be the beginning of a tragedy... Or was it maybe the end?

Watch Kai trying to escape the hopeless situation with a past regret being his source of energy.

Meet the high school student Hashimoto Kazuya, who reunited with his childhood friend Kawarumi Shizuka. What should have been a happy occasion turned out to be a bittersweet one. The girl, once known for her beaming smile, was now a girl who would never smile.
Will Kazuya be able to make her smile again, or will fate have another plan for the two of them?

It's about a student who hates school because of teachers and decides to become a teacher himself. After graduation, however, his parents die in a car accident, so he starts smoking. 7 years later, he is one of the teachers he hated back then and is also hated by the students. After an incident with another student who started smoking because of him, he starts to improve himself and helps the students to improve as well.