After losing her father in a tragic accident, Yoon-ju discovers that his death, while he was working as the legal team leader for the Chisung Group, is tied to a dark secret within the company. Moon Do-kyung, the first-in-line heir to Chisung, proposes a contract marriage, and Yoon-ju accepts it to uncover the truth behind her father’s death. 'Our mothers aren't easily fooled,' he warns. 'If we're going to look like a married couple, you might even have to sleep with me.' Sleep with this man? To get revenge on the person who killed her father, Yoon-ju resolves to endure everything. However, she finds herself increasingly drawn to him. Moon Do-kyung’s behavior is strange, and she fears what will happen if she truly falls for him.