To become a human, a 999-year-old Gumiho, Shin Woo-yeo needs to fill his fox bead with human energy before he turns 1,000 years old. One day, a college girl, Lee Dam accidentally swallows Woo-yeo's fox bead.
Yoon Song Ah works as a marketer for a cosmetics brand. She enjoys her job and dreams of launching her own brand someday. Chae Hyun Seung is a fellow marketer who becomes attracted to Yoon Song Ah. He tries to develop a romantic relationship but Yoon Song Ah rebuffs his advances, not wishing to date younger men.