Leonardo da Vinci's most famous portrait has never had a confirmed sitter, and this film goes after the identity behind the smile. Art historians and researchers walk through the competing theories: Lisa Gherardini, wife of a Florentine silk merchant, has long been the leading candidate, but the film also weighs claims that the painting is a self-portrait in disguise, or an idealized composite rather than a real woman at all. Technical analysis of the canvas, brushwork, and underdrawing gets screen time alongside close reading of Renaissance records and letters that mention the commission. The film moves between Florence and the archives holding the scraps of documentation that survive, treating each clue as evidence in an unresolved case rather than settled fact. It does not land on a single tidy answer. Instead it lays out why, five centuries on, historians are still arguing about who is actually looking back out of the frame, and why that uncertainty is part of the painting's hold on people.