In the year AC2XXX, a world war broke out in the world, taking nuclear pollution as an opportunity. The war started in Europe and the United States and quickly expanded to other parts of the world, including Antarctica. After ten long years, the war finally ended. However, the economic and human losses caused by the ten years of war are immeasurable, directly leading to the collapse of the world.
At this time, the underground organization "Sanctuary" centered on the ancient city of Athens, under the leadership of the genius scientist R. Ryan, transitioned from underground to above ground, and grew and grew at an alarming rate, causing the world to form a post-war reconstruction system surrounding Athens, leading to the reconstruction of the world. As a result, "Sanctuary" became the largest organization after the war, monopolizing a number of weapons patents and major economic projects. In order to allow "Sanctuary" to continue to develop, Ryan also invested a large amount of money to establish Sanctuary College-including General Education College, High School College and University Research Institute, which specializes in cultivating various talents needed by "Sanctuary". Among them, the "Sanctuary Academy" high school is one of the few ten autonomous student colleges in the world. Its management system is its own. The highest power in the college is held by the members of the student union, the Zodiac. Therefore, the members of each Zodiac are all elites in the world. Taking into account the college's autonomous system, the members of the Zodiac are replaced every term - that is, every five years.