Two years ago, black vortices appeared all over the world.

When countries worldwide investigated, they discovered these vortices were gates to another world, leading to dungeons teeming with monsters.

It was also learned that the dungeons operated under "certain laws" different from the real world, and modern weapons like bullets and rockets were ineffective against powerful monsters.

Nevertheless, by accumulating discovered facts, humanity developed a guide—a flowchart—on how to conquer them, outlining the progression from novice to expert within two years of the dungeons' appearance.

This flowchart was then used to facilitate the conquest of dungeons in various regions.

The protagonist, Odawara Akira, is a subculture otaku who loves anime and light novels, prioritizing subculture over the three basic human desires.

After medicines capable of curing injuries and illnesses were discovered in the dungeons, he began gathering information for his own ambition, creating his unique, original chart.

Indeed, his goal was to find the elixir of eternal youth and longevity—a secret nobody had yet discovered in the dungeons—so he could continue his otaku activities forever.

To achieve this ambition, Odawara Akira continues today to follow his original chart, all while pretending to be an arrogant explorer to avoid making companions.