Kotachi isn't exactly a social outcast- he has 1 whole friend- but he's not super outgoing either. Added to his lack of being social, he's been able to see specters since he was 10- a type of creature that lurks in darkness and harness energy from creatures, but are invisible to almost the entire world. In order to combat these creatures, weapons formed from constellations were dropped all around the world centuries ago. Armed with a pair of revolvers after the constellation Perseus, Kotachi fights specters at night and makes a few unexpected friends along with way- including a few human constellations, the Zodiac.