Upon arriving for a business appointment with a friend, MacKenzie learns that the man was killed by the brother, Bobby, of Nan Allen, a young woman he was in the act of assaulting. Bobby was coming home after playing cards and drinking hears a glass chimney break and rushed in break up the assault and shot the Colonel's friend who fell out the window. The Colonel finds this hard to believe, but upon getting to know Nan, he takes a strong liking to her. He decides to go into business with Nan and her brother who run a shipping business. He and Bobby go on a trip over the Laramie mountains to find feeding stations for the Colonel's cattle. When Bobby is injured by an avalanche, MacKenzie brings him to Shiloh and sends for Nan. They stay there while he recuperates. As he and Nan begin to fall in love, MacKenzie starts to wonder why more than one man in her past has died violently, and if Bobby's strangely possessive attitude has something to do with it.