The BAU travel to Montana to investigate a mass murder shooting at a gas station. By witness accounts, a young male/female couple were the shooters. Evidence at the scene suggests that the couple are newlyweds, that the shooting was not planned, but that the shooters' primary need is to please each other. The BAU know that they will kill again. When the unsubs end up having another killing spree at an alcoholics support group meeting, the BAU believe that the unsubs are recovering alcoholics themselves who met at a support group meeting, but who have violated what is known as the thirteenth step of getting involved with another in the program. Piecing together the clues, the team are able to identify the male of the couple as Ray Donovan, and ultimately the female as Sydney Manning. Knowing their identities leads to knowing their next intended hit. That results in a standoff with innocent hostages involved. The team use the knowledge of Ray being a sociopath and Sydney being a psychopath to try and end the standoff. Meanwhile, Prentiss receives some distressing news from an old work colleague named Sean McAllister.