In the Buenos Aires art world, a master forger has achieved legendary status. Rumored to be a woman, she seems especially gifted at forging canvases by the painter Mariette Lydis, a portraitist of Argentine high society. But who is this absurdly gifted creator of counterfeits? What motivates her? And what is her link to the community of artists who congregate, night after night, in a strange establishment called the Hotel Melancólico? On the trail of this mysterious forger is our narrator, an art critic and auction house employee through whose hands counterfeit works have passed. As she begins to take on the role of art-world detective, adopting her own methods of deception and manipulation, she warns us "not to proceed in expectation of names, numbers or dates... My techniques are those of the impressionist." What follows is a highly seductive and enveloping meditation on what we mean by "authenticity" in art, and a captivating exploration of the gap between what is lived and what is told. Portrait of an Unknown Lady is, like any great work, driven by obsession and full of subtle surprise.