One day, middle school student Daesung Han suddenly falls into hell, which had a game-like system. After fighting to survive for 80 years, he finally defeats the Demon God, and a message pops up asking "Would You Like to Return to Earth?" He accepts, and wakes up in a hospital bed, having been in a vegetative state ever since he fell into hell. Only 10 years had passed on Earth, and during that time, wormholes called Gates teeming with monsters from another dimension began appearing, which are dealt with by professionals known as Hunters. Daesung struggles with the harsh reality of losing all the power he'd gained in those 80 years, when suddenly a quest pop-up from hell appears.