Ha Yoon-seo has worked hard her whole life: after raising her younger brother alone, she is now a marketing manager at a credit card company. Her life takes a dramatic turn when she discovers that her boyfriend, Seo Ju-won, is the heir to the family that owns the company! Upon learning of their relationship, Ju-won's mother offers Yoon-seo money to break up with him, and Yoon-seo accepts. However, Ju-won is determined to win her back and will stop at nothing to reclaim her heart. Can Yoon-seo and Ju-won overcome obstacles and find their fairytale ending, or will reality tear them apart?