By means of a first person narration led by the fairy Melusina –key figure in the medieval imaginary– in his novel El unicornio (1965) Mujica Lainez subverts dominant sex-gender patterns and incorporates desire forms that, had they been localized in an Argentinean and contemporary context at the moment they were written, could have resulted particularly problematic. Thus, the reconstruction of medieval characters and motifs arises as a strategy to articulate erotic possibilities that dissent from dominant rigid morals in Argentina during the mid 1960s.A través de la narración en primera persona del hada Melusina –figura clave del imaginario medieval– en su novela El unicornio (1965) Mujica Lainez subvierte patrones sexo-genéricos dominantes e incorpora formas de deseo que, de haber sido localizadas en un contexto argentino y contemporáneo al momento de la escritura, hubieran resultado particularmente problemáticas. La reconstrucción de personajes y motivos medievales constituye, en numerosos pasajes, una estrategia para articular posibilidades eróticas que escapaban a la rígida moral impuesta en la Argentina de mediados de la década de 1960.