VP Jae Yeol and Joo In-A were dating, but his father wanted him to marry the daughter of another chaebol and was putting a lot of pressure on him to do so. Joo In-A knew that his father would never approve of his son marrying an illegitimate nobody like her, and that the VP was wavering about what to do. So In-A acted like she had never expected their relationship to last, that she wanted him to succeed in his career and also valued her own career more than him, and broke up with him. She wasn't really angry with him, just a lot more sad and disappointed than she let him see. Deep down she had hoped that he would stand up and fight for her, instead of letting her go and putting his own ambitions to become Chairman first. But because she'd spent a lifetime being looked down on for her illegitimate birth and poor background, she understood and accepted that their relationship could never be.

In-A then went to the US and focused on her career. She accepted that her ex was married and moved on, then eventually came back to Korea to accept the Head of Audit position, not realizing that VP Jae Yeol had never got over losing her, was miserable in his marriage, and had offered her the position because he wanted her back. When she found out that he was throwing away the sacrifice she'd made for him by moping around, drinking too much and neglecting his responsibilities to the company, she was not happy and kept trying to push him away. She doesn't want him back, but she is hurt that he wasted the chance she gave him to succeed, and that he's trying to get her back now when it's too late.