Ajiro Shinpei returns to his hometown of Hitogashima after two years to attend the funeral of his childhood friend Kofune Ushio. While reuniting with Ushio’s younger sister Mio and his best friend Sou, he learns about Ushio’s mysterious cause of death and the legend of the “shadow disease” passed down through the ages. The legend of the shadows—it is said that anyone who sees a shadow with their appearance will die. Ushio was said to have seen that shadow. The shadows of death haunt Shinpei and his friends. Eventually, the day of despair visits Hitogashima. “How can we save our friends, protect the islanders, and avoid death?…” Shinpei is forced to constantly think and make decisions in order to avoid despair, but every choice may only open a new door to despair. But he cannot afford to stop thinking and making decisions. To overcome the three days of despair.