February 1, 2307. A city in South Korea named Seodu City. In this era, cybernetic modification and coexistence with robots have become the norm, and people enjoy their flashy urban lives. However, dangerous days began to plague the city, though no one knew exactly when it started. The era of the Objects. They spread as rapidly as a sudden epidemic. We describe this phenomenon as a Bloom. A "Bloom" refers to the portals through which "Objects" emerge. Since Objects can pass through them, we can too. Those portals lead to other planets, leading us to believe the Objects are extraterrestrials. Consequently, humans began developing means to fight back, one of which is the Saber program. "Sabers" are individuals created to protect others from the Objects. Thus, we began a perilous coexistence with the Objects.