Sim Yeol-guk, a wealthy merchant of Joseon who was called the Money King through his high-priced art dealings. One day, his only son Hong-rang (8 years old ) goes missing. Sim Yeol-guk and Lady Min spend a great deal of money and people to find their son and even put a bounty on his body, but they find no clues. Jae-i (9 years old ), the daughter born from a concubine, is imprisoned in a separate building as punishment for stealing Hong-rang's guardian amulet, and Mu-jin (11 years old ), who is of noble blood, is brought in as his adopted son. The two, who became siblings overnight due to a tragic accident in their family, grow up relying solely on each other in the cold-blooded merchant class. Ten years later, the slave hunter Dokgae finds Hong-rang and brings him home. A grand feast is held, but in the noisy merchant class, Jae-i and Mu-jin are the only ones who are convinced that Hong-rang is a fraud and spew contemptuous words at him. However, as time passes, Jae-yi becomes confused by Hong-rang's sincerity and eventually accepts him as his real brother, but at the same time, he falls helplessly for his charm. The excitement of his brother's return is short-lived, and Jae-yi becomes heartbroken as he cannot let go of the love that he should have. When Mu-jin loses his position to Hong-rang and, to make matters worse, even Jae-yi's heart is stolen, he becomes obsessed with tracking down Hong-rang. What is Hong-rang's true identity? A clever tightrope walk continues between what each person wants to believe and what they don't want to believe, and in the end, the taboos and contradictions of the times, their ugly faces are revealed in a major twist, and the whole situation is turned upside down in an instant. Who really swallowed the gold?
