Even angels give into temptation. Once God's right-hand warrior, the archangel Agnes has succumbed to desire and formed a contract with Lucifer, the ruler of demons. Now as fallen angel, she poses as a simple taxi driver and patrols the bustling city of Seoul during the midnight hours. Cursed by the king of hell to seek souls for her life force, Agnes pursues depraved individuals who prey upon innocents for their own pleasure and uses their carnal desires against them. But when her past comes back to haunt her, a tantalizing game of cat and mouse involving vengeful entities ensues.