Trelkovsky, a Polish immigrant residing in Paris, moves into an apartment vacated by a young woman who committed suicide by leaping out of her window. Upon moving in, Trelkovsky begins feeling that the woman's personality traits are being thrust upon him. At a local shop, the proprietor offers him the breakfast and cigarettes that the woman usually purchased-and he accepts them. Holed up in the psychotic environment of a dark Parisian building that's peopled with odd characters, Trelkovsky feels himself overcome by a kind of madness. His slow mental deterioration finally compels him to emulate the woman's final, tragic hours.