Kang Ji-yoo is a ballerina, the girlfriend of Yoo Kang-woo, heir of Moseong Group. 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. To pay for her huge debt, she entered the Yoo family (with no idea about Kang-woo's identity or their past due to her amnesia) to be the nurse & guardian of Moseong Group's chairman Yoo Man-ho (Kang-woo's father). 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.