Cha Dae-Woong (Lee Seung Gi) accidentally releases a gumiho, a legendary fox with nine tails who was trapped inside of a painting of Grandma Samshin (三神). He does this by adding nine tails to the fox. The gumiho wanted to be human before, but was not able to fulfill the requirement of finding a husband, because a rumor was spread claiming that she eats the livers of humans. During their first encounter, Dae-woong experiences a life-threatening fall, and the gumiho saves his life by giving him her fox marble (여우 구슬). Later on, Dae-Woong wakes up and meets a pretty girl, not knowing that she is the gumiho that he released. When Dae-woong finds out about what he did, he must try to keep her happy and hide the fact that she is a gumiho from everyone. However, because Dae Woong has gumiho's bead that saved his life, he has no choice but to let her stay with him.