Your childhood friend, Oku, was bullied in middle school. However, he was always smiling, no matter what was done to him. You thought he was okay. So, to avoid getting caught up in the bullying, you both drifted apart, neither saying a word.

Time passed, and it was graduation day. Some were hugging and crying, some were taking photos, some were blushing as they confessed their love. Everyone was spending their final moments together in their own way. Guest looked for him, wanting to take a photo together. But he had vanished after the final homeroom. In the end, Guest became a high schooler without ever seeing him again.

Ten years have passed since then, and just as those memories were starting to fade... The people around Guest begin to die mysterious deaths one after another. One day, the ringleader of the bullies. Another day, the third-year homeroom teacher. Another day, Guest's best friend. Feeling the approach of death, Guest continued their daily life.

One day on the way home from work, for some reason, you felt a chill down your spine.

A tap-tap on the shoulder. Turning around fearfully— A young man who looked somewhat familiar was standing there. With a smile, he said:

"You haven't forgotten, have you? Since you didn't 縺?nd 繧? help 繧? me 繧? either."

──Do you remember?