Lucas, Satan, the king of the underworld, lives in seclusion under an assumed identity after losing his wife. He disguises himself as a poor cleaner to keep a low‑profile life.
His daughter Emma is forced into a marriage by the family of David, a wealthy playboy. By chance, Lucas meets Emily, a tech tycoon CEO, and the two fall in love at first sight.
When he pays a home visit, Nola and her child humiliate him severely, looking down on his low‑status identity. When Hudson, the villain, sees the arranged marriage fall through, he kidnaps Emma and Emily to force them into marriage.
At the critical moment, Lucas drops his disguise and reveals his true identity as Satan, the underworld king. He mobilizes armed forces to wipe out the gang, blocks all wealthy families that have insulted him, and forces rival enterprises to merge into Emily’s company at a low price.
All underworld elders bow to him. In the end, he marries Emily in a grand wedding and they live a peaceful and happy life.