The Hawkline Monster: A Gothic Western

Blurb

The Hawkline Monster: A Gothic Western is a novel by Richard Brautigan written in 1974.
Taking place mainly in eastern Oregon in 1902, the story concerns a pair of morally ambivalent gunmen, Cameron and Greer. On a job in Hawaii, they are stopped by the fact their target is with his son. After returning to California they spend some time in a brothel, where a young Native American-looking woman, Magic Child, comes to hire them for a job at her house. Along the way they stop at a place to eat and during the meal hear loud gunshot-like noises. That night Magic Child sleeps with both men and Greer takes quite a liking to her.
When they reach the house, in the middle of the western plains, it is surrounded by snow. Miss Hawkline comes to greet them and they realize that Magic Child is her twin sister. As soon as they enter the house the women's personalities change and they explain that they brought the men here to hunt down and destroy the "monster" living in the "ice caves" beneath the house.