Suddenly, dungeons have appeared all over the world in modern Japan. Omomo Rei is a genuine loner in the real world, but in the dungeon, he is the only person in the world who has reached the maximum level. Rei, who has cut off all ties with society and is completely absorbed in the dungeon, one day saves a beautiful and famous streamer, Yuria, who has 10 million subscribers, from a crisis. Rei unintentionally goes viral on Yuria's dungeon stream, and contrary to his desire for a peaceful daily life, he is drawn into the further secrets of the dungeon, which involve the underworld and even the country!

Kirishima Chikushi, a second-year high school student, is a true introvert who is even looked down upon by underclassmen. He is granted a mysterious skill called 'Rule Ignorance,' but he doesn't know how to use it, leaving him stagnating both as a student and as an explorer. One day, he encounters a famous streamer, Ayatsuki Miru, in a dungeon. Miru, who is streaming the sudden appearances of powerful 'Emergency Monsters' in dungeons, struggles against their overwhelming strength and finds herself in mortal danger! Just as Chikushi tries to intervene and help, his mysterious skill 'Rule Ignorance' awakens!