You get hit by a bus in the first ten minutes and survive it, and the show immediately stops caring about how. What it cares about is the weight of what comes next: a government that will dissect you, fellow immortals who want to use you, and the person you were before dying the moment anyone finds out what you are. The Black Ghost, that thing you can summon but barely control, becomes the only part of you that feels alive while everything else is hunted. Kei's powerlessness despite being unkillable is the real horror here. This is survival stripped of heroism: just a kid learning how much cruelty he's willing to become in order to stay breathing.
A bus hits Kei head-on, and he should be dead. Instead, he wakes up whole, unmarked, and terrified. He's an Ajin, a rare immortal being that government agencies have been hunting for decades. The moment his secret surfaces, Kei becomes prey: trapped between relentless authorities who see him as a research subject and other Ajin with far darker agendas. Survival means learning to weaponize his newfound immortality. Kei discovers he can manifest a devastating phantom called a Black Ghost, a manifestation of pure power that obeys only his will. But raw ability means nothing without control, and control is something he's desperately short on. The clock is ticking. Authorities close in. Fellow Ajin play dangerous games with human lives. Kei has to figure out who to trust, what he's truly capable of, and whether staying alive matters if it costs him his humanity. Every confrontation pushes him closer to the edge, where the line between victim and monster starts to blur. Survival isn't guaranteed. Neither is the person he'll become.