Dazai Osamu always wanted to die normally. He desperately looks for a way to become a normal person and when he asked for help, Ranpo Edogawa told him that there is a way to break and remove his ability. However, it's not just a simple way. Dazai has to nullify someone's ability permanently and as a consequence, he'll die. On the other side, Chuuya Nakahara has been always called out as a monster because of his Arahabaki form. He wanted to live a normal life and be treated as a normal person. When they met, Dazai told him that there is a way for him to remove his ability and asked him if he wanted to be the one whom he'll nullify permanently. It complicates things when Chuuya fell inlove with Dazai and when Dazai realized that Chuuya slowly becomes the reason why he wants to live again.