Two years have passed since Nezumi promised Shion they would meet again and departed from No. 6. In this sequel to the original story, Shion now serves as the chief of the Reconstruction Committee, where he is concerned about both the city's unstable political climate and the mysterious assassin targeting him. Feeling overwhelmed, he yearns for Nezumi's help, and Nezumi reappears just when he is needed most. Finally reunited, Shion vows that if Nezumi leaves again, they will go together. But first, can the two boys build a future that welcomes everyone? And will they be able to find hope amidst the traps that stand in their way?