Original: 결혼계약
A poor, widowed woman desperate to support her 7-year-old daughter and a wealthy business executive with a sick mother enter into a contract marriage.
On the day that Hye-soo goes to apply for a job at a restaurant named The Promise, she saves her daughter Eun-seong from getting hit by a car.
Hye-soo volunteers herself for marriage after overhearing Ji-hoon's conversation. Chaos breaks loose when loan sharks show up at the restaurant.
Hye-soo decides to marry Ji-hoon in exchange for money to take care of Eun-seong. The new couple starts prepping to prove their relationship is real.
Hye-soo gets interviewed at the hospital with Ji-hoon, but their caseworker wants to see Eun-seong. Grudgingly, Ji-hoon tries to win Eun-seong over.
Na-yoon shows up at Ji-hoon's place while Hye-soo is visiting. Ji-hoon rejects her advances and introduces Hye-soo to her as his fiancée.
Hye-soo goes out to eat with Seong-gook and Ji-hoon. Keeping their story straight, Hye-soo tells Seong-gook that Ji-hoon is really a warmhearted man.
Ji-hoon takes Hye-soo to the hospital for her fever, but Hye-soo goes home without treatment out of fear of having her illness found out.
Seong-gook has put a stop to the surgery after learning about Ji-hoon's plans. Mi-ran gets harshly criticized for possibly ruining her son's future.
Mi-ran decides to spend the rest of her natural life in her hometown. Ji-hoon sets out to find Mi-ran with Hye-soo and Eun-seong at his side.
Hye-soo visits the hospital and decides to receive treatment after going back to Seoul without Ji-hoon. Ji-hoon acknowledges his feelings for Hye-soo.
Ji-hoon is shocked to hear from Hye-soo that she accepted the remaining money from Seong-gook. Hye-soo decides to stop working at the restaurant.
Ji-hoon apologizes to Hye-soo and tells her that he wants her to stay by his side. Eun-seong cries and begs for Hye-soo not to leave Ji-hoon's place.
Hye-soo turns Ji-hoon down when he tries to convince her not to divorce him. Ji-hoon declares to Seong-gook that he will not give up on Hye-soo.
Ji-hoon offers Hye-soo the ring again after their blissful moment together. A rumor spreads about Ji-hoon being involved in illegal organ-trading.
Ji-hoon talks to Hye-soo and Eun-seong about looking for a place for them to all live together. Hye-soo's tumor has grown faster than expected.
Hye-soo collapses on the way to her new place. She undergoes surgery, but could still faint at any moment. Ji-hoon prepares to look after Hye-soo.
