The animated story of "The Duke's Contracted Fiancee" tells the story of Park Eun-ha, a high school repeater who died inexplicably and then inexplicably possessed a character in the novel. However, the person to be possessed was not the protagonist, but a supporting character who was about to die! In order to avoid the fate of a short life, she made a deal with the male protagonist in the novel. However, things are not that simple. The Duke has an angelic face but his heart is more vicious than the devil... Can she escape from the fate of a short life?