Synopsis
After giving his life to rescue a homeless man from a speeding train, Kei Kurono regains consciousness in a peculiar room alongside several other freshly dead individuals and a mysterious black orb. While they attempt to make sense of their situation, the sphere unveils a collection of weapons and black bodysuits, then orders them to eliminate an alien before teleporting them to an unfamiliar destination. With few explanations, Kei teams up with his childhood friend Masaru Katou and an unnamed woman. As they explore their surroundings, they soon understand that they have entered a grim and treacherous realm filled with constant threats.