S2E12 · Aubrey

In the town of Aubrey, Missouri, local detective Betty June "B.J." Morrow tells Lt. Brian Tillman (Terry O'Quinn) that she has gotten pregnant from their affair. Tillman asks B.J. to meet him at a motel later that night. While waiting for him, B.J. has a vision that leads her to a field where she digs up the skeletal remains of an FBI agent.

Agents Fox Mulder (David Duchovny) and Dana Scully (Gillian Anderson) head to Aubrey, where the remains are identified as belonging to Agent Sam Chaney, who disappeared in the area with his partner, Tim Ledbetter, in 1942. The agents find discrepancies in B.J.'s story, but Tillman comes to her defense. Mulder tells Scully of the case Chaney and Ledbetter were investigating, which involved the rapes and murders of three women with the word "Sister" slashed on their chest. Discovering similar cuts on Chaney's chest during the autopsy, B.J. instinctively realizes that the cuts spell the word "Brother." B.J. admits her affair and pregnancy to Scully.

Tillman reveals that a new murder has occurred where a woman had the word "Sister" slashed on her chest. B.J. claims to have seen the victim in her dreams, which involve a man with a rash on his face and a monument which, after a quick sketch by B.J., Mulder recognizes as the Trylon and Perisphere from the 1939 New York World's Fair. Searching old mugshot photos, B.J. recognizes the man from her dream as Harry Cokely, who was arrested in 1945 for raping a woman named Linda Thibedeaux and slashing "Sister" on her chest. Scully believes that B.J. subconsciously recalled the case, since her father was a cop and may have discussed it. The agents visit the now-elderly Cokely, who lives alone after being released from prison in 1993. Cokely insists he was at home when the latest murder occurred.

B.J. awakens from a nightmare covered in blood, finding the word "Sister" slashed into her chest, and sees a young Cokely reflected in the mirror behind her. She heads to a stranger's basement and tears away the floorboards, revealing a skeleton that is found to be the remains of Agent Ledbetter. Cokely is arrested, but denies attacking B.J., insisting he's too old to even leave his house without his oxygen flask. Scully tells Mulder that blood on the latest victim matches Cokely's. The agents visit Thibedeaux, who describes her encounter with Cokely in the 1940s.

Mulder notices a photo of her at the 1939 World's Fair. When pressed, Thibedeaux reveals that the rape resulted in a child, which she put up for adoption. The FBI tracks down the child, who turns out to have been B.J.'s father, causing Mulder to surmise that B.J. is the killer and may be operating on genetic memories which tend to skip a generation.

As the agents are on their way to intercept her, B.J. attacks Thibedeaux, but stops when she sees the "Sister" scars on her chest. The agents find Thibedeaux after B.J. has left, and head to Cokely's house, believing him to be her new target. B.J., who has already arrived, cuts Cokely's respirator tubes and attacks him with a razor. As Mulder is looking for them in the house, he is attacked by B.J. She threatens to cut his throat with the razor, at which Scully and Tillman compel her to stop. B.J. finally surrenders after Cokely dies. She is then placed in a female psychiatric ward, where she is put on suicide watch after attempting to self-abort.