Jinsei Donzoko na Ore ga Tenseishitara Ossan ga Mote Hayasareru Sekai Datta Ken

This is the story of Mitsuki Fukuo, a middle-aged man who, despite his age, remains a virgin. He works as a teacher at an academy. He is ignored by those around him and has almost no experience interacting with women. Everyone who saw him would say in unison, “What a dirty old man…”
He was used to hearing this, but there was a gaping hole in his heart.

One day, on his way home from work, completely exhausted by everything, he was walking in a daze when suddenly a truck crashed into him. He froze in place, unable to do anything, and his body flew into the air.