The team travels to Rapid City, South Dakota after Reid, who is suffering from insomnia, stumbles across a case. Two thirtysomething men in separate incidents were found dismembered in the area, one in Rapid City, another in a nearby native reserve. The men were also poisoned with a natural herb. Both men were also not local, they being associated with the seasonal logging industry. When a third man, Chad Dumont, goes missing, he who is also not local but a military man on furlough, the team refocuses on the non-local aspect. Ritualistic markings on the bodies also leads to the team looking into the native angle as well as the naturopathic angle. After doing further interviews, they determine that the unsub is a woman who is luring the men away using the ruse of sex. The team has to piece together all these clues to find the unsub and her motivation. Meanwhile, Rossi tries to help Reid understand the cause of and deal with his insomnia.