Go Eun-sung (Han Hyo-joo) was studying overseas in New York and returned to Korea during her vacation to bring her autistic brother, Eun-woo (Yeon Joon-seok), to the United States to study music. Sunwoo Hwan (Lee Seung-gi), who was also studying in New York, was ordered to return to Korea by his grandmother, Jang Sook-ja (Ban Hyo-jung), to learn how to manage her food company. Eun-sung and Hwan, who were on the same flight back home, accidentally had their luggage bags exchanged, which led to several misunderstandings between the two.
Go Pyung-joong (Jeon In-taek), Eun-sung's father, was struggling to save his company from going bankrupt. One day, his wallet and valuables were stolen by a thief who subsequently died in a gas explosion accident. The police, upon finding Pyung-joong’s belongings on the thief, mistakenly identified the thief as him and a death certificate for Pyung-joong was promptly issued. He decided to lie low and not tell his family that he was alive so that his family could claim his life insurance money and use it to clear the debts. However his second wife, Baek Sung-hee (Kim Mi-sook), kicked her stepchildren, Eun-sung and Eun-woo, out of the house after collecting the insurance money and moved into a new home with her daughter, Yoo Seung-mi (Moon Chae-won). Seung-mi was also Hwan's longtime best friend, hoping to be something more.
Eun-sung asked for help from several of her friends, including Hyung-jin, who avoided her because she was no longer rich. She managed to find a job at a nightclub with the help of her friend, Hye-ri. At the nightclub, Eun-sung met Hyung-jin's upperclassman, Park Joon-se (Bae Soo-bin), who was shocked to see her working there. She also met Hwan, who caused her to lose contact with Eun-woo. Realizing that Eun-woo was missing, Eun-sung was devastated and tried searching for her brother but to no avail. With the help of Hye-ri and Joon-se, Eun-sung rented a small room and started a small dumplings stall while continuing her search for Eun-woo.
Meanwhile, Sook-ja became deeply disappointed in her grandson as Hwan had no direction in life and did not know how to cherish her company and employees. While pondering over what to do about her grandson, Sook-ja visited a neighborhood that she used to live in when she was poor and encountered Eun-sung, who was selling dumplings. Sook-ja encountered an accident and received help from Eun-sung. Seeing that Eun-sung tried her best to take care of her even when she could not afford her own daily expenses, Sook-ja was touched by Eun-sung's compassion. She brought Eun-sung home, then announced to her family that Eun-sung was going to live with them and that she was going to appoint Eun-sung as the heir of her food company, if she could raise the profits of the sinking second branch by 20%.