Through blurry eyes, Noah Barloc stares out at a world torn asunder by chaos and war. He's been wandering in it far too long, alone and starving. He slumps down beside the rubble of some building, prepared to accept the end. The shadowy figure of a man appears on the horizon right before Noah's world goes dark. Noah awakens in this man's home, and learns the world is not so broken as he thought. Mankind has built cities underground and is thriving. Noah looks to his savior, Ban Reed, for guidance in this new world.
Ban is a hardened survivor of the Last War. He makes his living building bionic limbs for other survivors who, like him, lost limbs to the War, and hides his true, caring nature behind a cold, sarcastic facade. But for reasons unknown to Noah and Ban's friends, Ban invites Noah into his home to recuperate, and then teaches Noah the trade of building exceptional bionics so that he can support himself.
A recent bad breakup turns Ban from a one-man show into a loose cannon that brings home a new sexual partner every night. Noah has come to care for Ban, to see past his cold exterior into that warm, caramel center. Noah can't stand hearing the sounds of Ban's nightly sexual romps, and can't help wondering why Ban refuses him when he's the one willing to give Ban the love and devotion he knows deep down that Ban wants.