William Munny is a retired, once-ruthless killer turned gentle widower and hog farmer. To help support his two motherless children, he accepts one last bounty-hunter mission to find the men who brutalized a prostitute. Joined by his former partner and a cocky greenhorn, he takes on a corrupt sheriff.

In 1960s Wyoming, two men develop a strong emotional and sexual relationship that endures as a lifelong connection complicating their lives as they get married and start families of their own.