Kang Hye Mi is an office worker who's been at KS International for 4 years. She used to always be confident and energetic but lost her confidence and her faith in love after witnessing her scum ex-boyfriend cheating on her. To make matters worse, her ex-boyfriend is a general manager at her company, and she can't avoid running into him. Like with all office romances, after breaking up with him, she becomes the topic of all kinds of rumors. The stress and difficulties have been enough for her to constantly consider resignation. One day, she bumps into Na Jung Gook on her way to work and misses the bus, ruining an important presentation. Ironically, Na Jung Gook is joining Kang Hye Mi's team as a new employee, and they become a mentor and mentee. Na Jung Gook is a rare newcomer who is passionate about everything, without avoiding his boss and who lives by maintaining a work-life balance.