The blackboard in a certain second-year high school classroom suddenly transformed into a display.

Along with the message, "Welcome to the World of Deep Dungeon," they were forced to draw from a gacha.

Although it was a game, it was a brutal otherworld that demanded they physically fight monsters using the power drawn from the gacha.

Outside was pitch black, and a path forward was shown, but the sudden event caused a stir among the classmates.

However, Sakaki, the student council president, and Kanzaki, the class's mood maker, took the lead, rallied their classmates, and began to conquer Deep Dungeon.

――Meanwhile, Matsui, a born loner who remained outside their circle, quietly ventured into the dungeon, while asking "the knowledgeable dolphin"—which possessed a modest ability to explain the game—about how to proceed. In contrast to his classmates, who faced the challenge with grim determination, he had a leisurely expression.

※Also posted on Kakuyomu.