Shin Woo Yeo is a handsome and smart writer, who is actually a 999-year-old nine-tailed fox. To become a human, he collects human energy in a bead. One day, the drunk friend of Lee Dam, a university student, falls asleep on top of an expensive car whose owner is Woo Yeo. While Lee Dam struggles to take her friend away and Woo Yeo trying to help her, Woo Yeo's bead accidentally falls out of his mouth, and Lee Dam unintentionally swallows it. The bead can exist inside of a human for no more than 1 year and, afterward, the bead will break inside of that person causing the person to die. Not wanting to lose his chance in becoming a human, Woo Yeo explains to Lee Dam their predicament and suggests living together until they figure out a solution. Lee Dam, who has never had a boyfriend in her life, now lives with Shin Woo Yeo.