To repay the debt left by her parents, Seo Won infiltrates the large corporation Eln as an industrial spy. But of all people, her target, Vice President Kang Jun, only hires male assistants! In order to achieve her goal, Seo Won ends up disguising herself as a man and gets a job as the VP’s secretary. From the moment she joins, she’s overwhelmed trying to attend to the demanding Kang Jun while secretly stealing company information as a spy. Amidst all this, Seo Won and Kang Jun begin to feel an inexplicable attraction toward each other. Already busy searching for confidential information as a spy, Seo Won becomes entangled with Kang Jun, who shows desire even while thinking she’s a man, and Director Dong Jin, whose constant smile hides his true intentions. On top of that, Kang Jun’s arranged fiancée, Sarah, approaches Seo Won, claiming she fell for her at first sight…! Can Seo Won manage to keep her identity as a woman a secret and complete her mission until the end?