The story takes place in a small city called Xingyuan City.
On Lion Tail Mountain in the city, there stands a huge object shining with colorful light. This object named "Mono's Corner" is actually the "Monster's Corner" that stood there after the "Monster Day" incident 16 years ago.
After the "Monster Day" incident, when monsters appeared at the same time around the world, monster disasters began to become daily. While Japan's Earth Defense Force began to use force to deal with monsters, the SKIP Scientific Kaiju Investigation and Prevention Center (collectively referred to as the SKIP Scientific Kaiju Investigation and Prevention Center) also continued to conduct scientific surveys and evacuation guidance in various regions in order to prevent the occurrence and expansion of monster disasters. To this day, this organization is still constantly investigating the reasons for the emergence of "Monster Day" and the "Mono's Corner" in the city.
Only 7-year-old "Yuma" was attacked by a monster while camping with his parents in Lion Tail Mountain. He miraculously survived without injury. Taking this as an opportunity,"Yuma" embarked on the path of studying monster biology. Although there is a painful past...
