Mudou Setsuna used to think he was a regular guy. He grew up in a broken home, went to school, and got into fights every now and then. Nothing out of the ordinary.. except for his uncontrollable crush on his own sister, Sara. Things begin to get even more confusing for him as he discovers that he is the reincarnation of Alexiel, a high angel who rebelled against God after she witnessed appalling atrocities in Heaven. Pursued by his mother, the police, demons, and Alexiel's half crazed angelic twin, Setsuna is confronted on all sides while living with the guilt of his forbidden love. The stakes are higher than he knows, because if his celestial counterpart happens to be reawakened during the chaos, it would mean the destruction of the entire city.