"Concrete Revolutio: The Last Song" is the second season of the "Concrete Revolutio" series, continuing the complex narrative of a world where superhumans, aliens, and supernatural beings coexist with humanity. The story is set in an alternate version of Japan during the 1960s and 1970s, blending historical events with fantastical elements. The Superhuman Bureau, a government agency, is tasked with managing and protecting superhuman entities while maintaining public order. However, the line between justice and morality becomes increasingly blurred as the series explores themes of societal prejudice, ethical dilemmas, and the consequences of wielding extraordinary power.

The protagonist, Jiro Hitoyoshi, is an idealistic agent of the Superhuman Bureau who struggles with his own beliefs about justice and the treatment of superhumans. His journey is interwoven with a non-linear narrative structure, frequently shifting between past and present timelines to reveal the motivations and backstories of key characters. Jiro's relationships with his colleagues, particularly Kikko Hoshino and Emi Kino, play a central role in the story, as their differing perspectives on justice and humanity create tension and conflict within the Bureau.

The plot delves into the Bureau's internal struggles, external threats, and the broader societal implications of superhuman existence. Key arcs include the Bureau's efforts to prevent catastrophic events caused by rogue superhumans, the emergence of anti-superhuman factions, and the moral ambiguity of using superhuman abilities for political or personal gain. The series also introduces a diverse cast of superhuman characters, each with unique abilities and personal struggles, such as the enigmatic alien Fuurouta and the tragic figure of Claude, a former Bureau agent turned antagonist.

As the story progresses, the narrative builds toward a climactic confrontation between Jiro and those who seek to exploit or destroy superhumans. The final episodes tie together the fragmented timelines, revealing the full scope of Jiro's journey and the ultimate fate of the Superhuman Bureau. The series concludes with a poignant exploration of the cost of idealism and the enduring question of what it means to protect both humanity and those who exist beyond its norms.