The film traces back to Betty's hometown of Nyíregyháza in Hungary. The contours of her existence are slowly but surely becoming visible through testimonials from people who knew her intimately. The subject of Dirty Window is emphatically not the murder that has not yet been solved. Director Walter Stokman wanted to know who Betty was, where she came from, what her dreams were. In the documentary we meet Betty's father, who lives in dire circumstances apart from her mother, her music teacher and a friend who worked with her in the Red Light District but returned to Nyíregyháza for her children.