Kim Jae-hoon, a goblin who has lived for a thousand years, enters into a three-year contract marriage with Han So-hee, the only daughter of a chaebol family, due to a past connection. He lives as an ordinary son-in-law while hiding his true identity, enduring insults as he is misunderstood as incompetent by his father-in-law, mother-in-law, and wife. However, after their divorce, his true power is revealed amidst the chaebol family's crisis. The truth that he was the one who had been supporting this family is unveiled, and a satisfying reversal begins against his arrogant wife and the chaebol family.