Although it's not stated in the opening of the film, the description on Amazon Prime says that this film takes place in '1877 Arizona'. At the end of the film, Kate is shown dead, with a syringe in her hand and a very distinctive bottle of Bayer Heroin on the table. However, Bayer's Felix Hoffmann did not synthesize heroin until 1897 and Bayer did not trademark the brand name 'Heroin' until 1898.