On August 2nd 2376, dimensional cracks opened and monsters fled out of these, landing on earth. Ever since, humanity has been at the bottom of the food chain. After 50 years, when all hope was lost, the humans killed a dragon and got its martial arts technique and blood to generate martial artists, combating the beasts. Eventually, humanity has gained a footing in this new world. People eventually found out how to contract beasts, extract bloodlines and manipulate elements. These people were called Mutators. And when, Jack, an ordinary high school student, bullied by his peers, who fell to a crime of kidnapping and had his powers sapped from him, received a system, his life... changed.