Denci is a young man who lives in extreme poverty because of a huge debt left by his father. He saves the demon Bochita and kills low-level demons with it as a demon hunter in exchange for rewards. One day, a gangster tricked Denci into becoming a sacrifice for a bunch of demons. When Denci was dying, Bochita sacrificed himself and gave him his heart, which resurrected him and gave him the power of a demon. He could activate it by pulling the chain on the heart. After that, Denci was spotted by the public security personnel and became a demon hunter for the public security...