In this captivating Korean romantic fantasy, a 200-year-old demon named Jeong Gu-won, played with charismatic flair by Song Kang, finds his immortal existence turned upside down when he unexpectedly loses his formidable powers to a cold-hearted heiress, Do Do-hee, portrayed by Kim Yoo-jung. Do-hee, the CEO of a prestigious company who trusts no one, is forced into a contractual marriage with Gu-won to survive threats from those who covet her wealth and position. As the demon becomes her reluctant bodyguard, their unlikely alliance sparks a dangerous and passionate romance that challenges the very nature of his supernatural being. Blending dark fantasy elements with sharp romantic comedy, the series explores themes of redemption, trust, and the transformative power of love as the pair uncovers a sinister conspiracy linking their fates. With its stylish visuals and electric chemistry between the leads, My Demon delivers a thrilling mix of supernatural intrigue, high-stakes corporate drama, and swoon-worthy romance that keeps viewers guessing until the very end.