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.

The neighbors of a frontier family turn on them when it is suspected that their adopted daughter was stolen from the local Kiawa tribe.