Not a particularly good movie, but not particularly bad either. Acting, cinematography, soundtrack are all competent without being exceptional. Not worth looking for, but a halfway decent time-waster if happened upon.
Yvonne is a young woman mooching off her (I think?) roommate, who works in television. We know from the very beginning of the movie (and the video box) that Yvonne is going to murder someone. The plot is pretty simple: Yvonne tracks down Barbara, an old friend who physically resembles Yvonne somewhat, kills her, and takes over her life. Yvonne rather recklessly relies on luck to keep her imposture from being discovered. She's at risk of being found out both by the few people who know Barbara, and also by the few people who know Yvonne.
