One act of mercy destroys everything Shion thinks he is, and the show refuses to let him rebuild it into something safe. What starts as a privileged boy's naive mistake becomes a descent into a city designed to break people who ask the wrong questions. The animation carries you through quietly devastating character moments, then snaps you back with sudden violence, Bones knows exactly when to let you breathe and when to suffocate you. By the time you understand what No. 6 actually is, Shion has already become unrecognizable, and you'll realize the show earned that transformation in a way that made sense. The middle episodes lose momentum, but they're building something darker than another action arc.

Shion lives in No.6, a walled city-state where a privileged elite enjoys a seemingly perfect life after a devastating world war. That life changes on the night of his 12th birthday, when he shelters a mysterious boy called Rat who has fled the city's Special Security Area. Helping him costs Shion his elite status, and he and his mother are moved out to the city's outskirts. Years later, Shion looks into a new string of mysterious deaths and ends up arrested on suspicion of murder. As he is being sent to the Correctional Institute, Rat reappears and rescues him. On the run together, the two must uncover the sinister secrets at the heart of No.6 if they hope to survive. A psychological sci-fi action drama adapted from a novel by Asano Atsuko.