A native of Jeju Island, Joo Yoo-rin lives with her father, who is addicted to gambling. Because of her father's debts, Yoo-rin has become particularly skilled at lying and grifting. When her father escapes the island to hide from his debtors, Yoo-rin is determined to support herself and clear up the debts by selling oranges illegally picked from a hotel orchard and working as a tour guide on the island. Then, one day, she meets Seol Gong-chan, the sole heir to the L'Avenue Hotel fortune.
To grant his grandfather's dying wish, Gong-chan employs Yoo-rin to act as his grandfather's long-lost granddaughter. Offering a monthly salary plus a bonus, he asks her to do what she does best - to put on an act. Not wishing to lie to a dying man, yet desperate for the money, Yoo-rin takes the offer and starts playing the long-lost granddaughter. Through a strange twist of fate, however, finding his granddaughter makes the grandfather so happy that he makes a complete recovery. Since they have claimed to be cousins, Gong-chan and Yoo-rin are forced to live together under one roof, and as time passes, the attraction between them grows. However, love is forbidden for these two, who must pass as cousins.