Decades have passed since the Human Union first launched the Mars Colonization Program. After many years of effort, people have successfully mastered a new space on this red planet, coexisting in harmony with the local inhabitants - insect-like creatures known as a Swarm. However, the calm was soon disturbed due to the known causes of the Swarm mutation. The inhabitants of the human race on Mars faced serious difficulties caused by these primitive creatures. What were once friendly neighbors have turned into hostile enemy relations. The preservation of human civilization and ensuring the safety of life on Mars have become top priorities. Understanding why Roy suddenly showed such aggression can help identify the root of the problem.