In
Greenwich,
Connecticut, a jogging couple find their neighbor, a young girl named Teena Simmons, standing alone in her driveway. After she explains her father is in the yard, the couple find him sitting dead on a
swing set with two incisions in his neck. When
FBI agents
Fox Mulder and
Dana Scully take the case, Mulder explains that he believes the death is an example of
extraterrestrial cattle mutilation on a human being. The agents meet Teena, who claims to have seen "red lightning" when her father died and that "men from the clouds" had wanted to "
exsanguinate him." Leaving Teena in the state's care, the agents travel to
Marin County,
California, where a similar death has occurred at the Reardon residence. Mulder and Scully realize that, despite thousands of miles lying between the two crime scenes, the killings were committed on the same day and at the same moment. Meanwhile, back in Connecticut, Teena is
kidnapped by a dark-clothed figure. When Mulder and Scully meet Mrs. Reardon and her daughter, Cindy, they discover that Cindy is completely identical to Teena. Cindy's mother tells the agents that her daughter was conceived via
in vitro fertilization at a fertility clinic in
San Francisco. There, Scully learns that both the Simmonses and the Reardons were treated by Dr. Sally Kendrick, who was eventually fired for conducting
eugenics experiments with
ova from the clinic's lab. Meanwhile, Mulder is contacted by
Deep Throat, who details a
Cold War-era
supersoldier program that produced genetically modified clones who were identified as "Adam" or "Eve" based on their sex. Deep Throat tells Mulder of a woman connected with the project who is currently kept in a mental hospital. Mulder and Scully travel to the hospital and meet "Eve 6", who bears an identical resemblance to Sally Kendrick. Eve 6 tells them that the Adam and Eve clones created for the program had extra
chromosomes which led them to display superhuman intelligence and strength, as well as extreme homicidal psychoses. The last three Eve clones—Eves 6, 7, and 8—were institutionalized after the project was cancelled. However, Eve 7 escaped and later joined the fertility clinic as "Sally Kendrick", modifying the ova of the clinic's patients to create new Eve clones. Eve 8, who also escaped, is still at large. Though Mulder and Scully place Cindy's house under surveillance, they're unable to prevent one of the escaped Eves from abducting Cindy. The Eve takes Cindy to a motel where Teena is already being held captive and introduces the two girls to each other. The woman reveals herself to be Eve 7/Sally Kendrick and explains that she cloned the girls using her own genetic material to improve upon the original program's flaws, only to learn about the girls' "accelerated development" after they murdered their fathers. She asks the girls how they learned of each other's existence and how they planned the murders, to which they reply that they "just knew." The girls poison Eve 7's drink with a fatal dose of
foxglove. Mulder and Scully arrive at the motel, only to find Eve 7 dead. The girls claim that both Eve 7 and Eve 8 were trying to goad them into a
mass suicide. The agents decide to take the girls with them as they leave the scene. That night, the group arrives at a roadside
truck stop and order drinks at the diner. One of the girls, however, discreetly poisons the sodas the agents ordered with foxglove. After finding odd stains on the diner counter, Mulder realizes the girls' plan and manages to keep Scully from drinking more of her soda. The agents then pursue the girls through the truck stop, with Mulder eventually capturing them. Teena and Cindy, now known as "Eve 9" and "Eve 10," end up in the same psychiatric ward as Eve 6. Eventually, a woman wearing a lab coat—and immediately recognized by Cindy and Teena as Eve 8—comes to the ward. When Eve 8 asks the girls how they knew she would come for them, the girls again respond: "We just knew." == Production ==