After a traffic accident, Kang Ji-yoo lost all of her memories, her family using up all their money to pay five years' worth of hospital treatments.

Chae Seo-rin was Ji-yoo’s best friend during high school, but was then raped on the orders of Byeon Il-goo.

She was then forced to work with him to become the biggest stockholder of Moseong Group, becoming Ji-yoo's enemy in the process.

She was found by Seo-rin after the accident and kept her in a nursing home (posing as "Hong Sun-bok"), forcing her mother to care for Ji-yoo thinking she has no hope of ever regaining consciousness.

Since regaining consciousness, along with trying to recover her memories and fighting the feeling of maybe having given birth to a child, she has been working as a nurse in the Yoo family to try to find out the real cause of the accident (as well as justice for her father's unjust death), her only memory a man with a wing tattoo.

Heir to Moseong Group, Yoo Man-ho's second wife's son, and Ji-yoo's boyfriend before the accident.

After Ji-yoo's accident, Sun-bok changed her name to "Chae Seo-rin" (after a gangster saved her) because she wanted to get out of the "nightmare" that was her poverty.

He resents his father for abandoning them, especially his mother (played by Lee Sang-suk) who had died of cancer.

Seo-rin took him away from his birth mother and deceived the Yoo family, claiming Ma-eum is her son with Kang-woo.