Imagine a world where humans are almost extinct. Hundreds of years ago, the realm walls collapsed, and Earth was flooded with mythical creatures. Now, dungeons dot the landscape, releasing demons that terrorize and destroy everything in their path. If they aren't stopped, humans won't be the only endangered species. To preserve life and win the war against demons, protectors from different species all over the world have downloaded level-up programs to help them fight. Jason Jonosan doesn't want to be a part of that world, though his dad created the original tech. His dad's latest work has made him a target, and Jason finds himself running for his life. When he's accidentally injected with an accelerated prototype, it's level up or die. But as he goes through dungeons with his best friend and new party members, they realize the situation isn't as simple as they always believed, and the race to save Jason's life turns into a quest to save the world.