After a severe accident leaves him critically wounded outside the hospital, a young man named Sora receives urgent care from nurse Yagami Yuu. In the emergency ward he meets director Mikage Reika, who offers him a place as a test subject for the facility’s research programs. With no relatives or connections beyond the hospital walls, Sora accepts the proposal and begins his recovery under Yuu’s attentive supervision. From that point his future shifts in ways he could never have foreseen.