A dungeon suddenly appeared on Earth, granting humanity newfound abilities. However, these powers were confined to the inside of the dungeon. The use of magic and the manifestation of supernatural abilities were only possible within the confines of the dungeon, leaving the real world largely unaffected. Despite this, the lives of many people continued unchanged. In the midst of this, the protagonist, a high school student, awakens to a skill known as “Gate,” a teleportation-like ability. With a displayed level in his hands, a new adventure seemed to unfold. On his way home from school, the protagonist decides to test the Gate skill at a normal street corner. In an instant, he finds himself standing in a different dimension, surrounded by unfamiliar landscapes. In this modern fantasy world, the protagonist levels up, learns magic, and hones various skills. He faces the mysteries of the dungeon, encounters new allies, and immerses himself in adventures different from the real world.