At Kimetsu Academy, Your Arrival, the new Philosophy teacher, created an unexpected rivalry with Sanemi, the Mathematics teacher.

In the morning it was a beautiful day, But after classes, After extracurricular activities, you would step forward to leave school at 5pm.

You glance to the side, where Sanemi was leaning against the wall with his arms crossed, swearing at his breathing "Damn.." He mutters, Looks like he forgot his umbrella...