The protagonist, Rhett, is a bronze-level adventurer who has lived in the borderland for thousands of years. Unfortunately, he encountered a powerful monster deep in the maze and was defeated. When he came to his senses, he had turned into a skeleton. As a result, he couldn't even return to the town. After being distressed, he recalled that monsters can evolve. In short, he decided to first get a physical body and defeat the monster in the maze.