The BAU is called in to Montana when a woman is kidnapped from a grocery store by a member of an anti-government militia, Francis Goehring. When he's cornered by police, he blows himself up with a grenade when he's cornered by police, but the woman is nowhere to be found. After digging into Goehring's past, they find his former wife, who points them to a location where it's likely the kidnap victim was taken. There they find her dead body, skin still warm. Goehring didn't commit the recent murder; he has a partner who's still alive. But he did commit three earlier murders, and Prentiss finds each of them buried in a rose garden.
Morgan and JJ question members of the local militia group, not learning much other than the partner's size. The team creates a profile of a submissive, slight built man who has been forced to take charge now that he's on his own. After watching tapes of Goehring torturing his victims, Prentiss has a realization: the unknown partner was in love with Goehring. He did Goehring's bidding, including his gardening, so the team searches local nurseries and gets a hit. Henry Frost worked at one of them, and once the BAU arrives at his home, Henry has destroyed everything of his own. He wants to transform himself into Goehring by kidnapping a young girl from a gas station.
Prentiss has a lead on where Frost would have taken the girl, and the team is joined by the head of the local militia, Harris, when they arrive. As Hotch distracts Henry, Harris takes him out, saving the girl.