Hex

Hex is a 1973 American Western supernatural horror film directed by Leo Garen and starring Keith Carradine, Cristina Raines, Hilarie Thompson, Dan Haggerty, Gary Busey, and Scott Glenn. Set in 1919, its plot follows a wayward band of motorcyclists who seek shelter at a rural Nebraska farm inhabited by Native American sisters Acacia and Oriole. When one of the motorcyclists, Gibson "Giblets" Meredith, tries to rape Acacia, Oriole places a curse on them, resulting in their subsequent deaths.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.