The couple go to a motel and have sex. Shortly thereafter the businessman begins convulsing and dies. Before Marty leaves the motel, her physique changes and she metamorphoses into a man. Mulder and Scully are assigned to investigate the case. Mulder links the death to a series of others in which victims died in the throes of passion.
Medical tests reveal large amounts of pheromones in the victim's blood.
He also links two of the murders to a remote town in Massachusetts inhabited by The Kindred-a sect of religious isolationists famous for their abstinence and pure Christian beliefs. The agents travel to the rural village, where sect members allow them access to their community only after they relinquish their guns. As Mulder and Scully dine with The Kindred, Brother Aaron suddenly begins choking. Scully is forbidden by the other sect members from aiding Brother Aaron, and he is led away. The agents perform some clandestine investigating during the night.