Man of Glass is a film about delusion and obsession, sanity and insanity, and the line between the two. The story unfolds against the backdrop of fin de siècle Paris, a turbulent period marked by the rise of the new 'sciences of mind'-psychology and psychiatry-and the development of new 'scientific' theories of madness and criminality. Disgusted with the mercantilism and vulgarity of the bourgeoisie, Gaspard de Ronsard, a decadent aristocrat, assumes the identity of a stranger only to find out that someone else has assumed his own identity.