Tsunayoshi Sawada, the junior president of Miskatonic University, died during a mission.
Then he returned to the twelve-year-old good-for-nothing Tsuna who belonged to Namimori Town before he time traveled.
Mistakenly believing that there are no indescribable things in this world, Tsunayoshi started his retirement life at a young age and lived like an invisible man.
Then, when he was fourteen, he met a little baby in a suit.
Then, the wall of the world cracked, and unspeakable things gradually descended on the world, including his old classmates.
Concept: The world is Azathoth's dream