David Greig's play The Strange Undoing of Prudencia Hart is set in a small Scottish border town on the winter solstice, and centres around the concept of liminality. Based on the traditional border ballad "Tam Lin," the play is a carnivalesque and ironic reinterpretation that builds upon various intersections of boundaries, particularly those between past and present, tradition and modernity, reality and fantasy, and the living and the dead. Prudencia, the protagonist, is an old-fashioned PhD student trapped between the conventions of the old world and the necessities of the modern world. Nick, the play's liminal character, is a devil appearing in human form. This article explores the play's themes of liminality and liminal personae, building on Arnold van Gennep's concept of the liminal space. The article analyzes how the play manipulates spatial, temporal, and societal boundaries and reveals the transformations that these liminal experiences create in the characters. Moreover, this analysis is designed to help understand the play's broader cultural and societal themes. Additionally, the article aims to examine how Greig's work tackles and reinterprets the traditions of the border ballad genre, and how this reinterpretation enriches the unique aesthetic and thematic qualities of the work. This approach demonstrates how Greig's work amalgamates traditional and modern elements to find a new and original way of narrating liminal experiences and transformations.