Kei Nagai and his new comrade Kou Nakano plot revenge against Satou, a fellow Ajin hellbent on global dominance, after escaping certain death. As Satou begins a series of public executions, the human race scrambles for a way to defeat the eternal tyrant. In the guise of high-ranking government official Yuu Tosaki, whose vast knowledge into Ajin provides him a tactical advantage in the struggle against Satou, and Tosaki's Ajin aide Izumi Shimomura, Kei finds unusual friends. As his faction grows in strength, Kei races against the clock to put an end to Satou's mission before it destroys civilization as he knows it.