After surviving a fatal accident, high school student Kei Nagai discovers he is an Ajin — an immortal being hunted by the government. Suddenly forced into hiding, Kei enters a terrifying world where Demi-Humans are feared, abused, and experimented on.

While struggling to survive, Kei encounters powerful Ajin with different ideologies, leading him into deadly conflicts that challenge his morality and humanity. Filled with suspense, psychological tension, and strategic battles, Ajin delivers a gripping supernatural thriller experience.