Season 4 Episode #19
Synchrony.

Jason Nichols and Lucas Menand, researchers at the Massachusetts Institute of Technology, become embroiled in an argument as they walk down a city street. They are approached by an elderly man, who warns Menand that he will be run over by a bus at exactly eleven forty-six that evening. Menand tells a campus security cop that the old man is harassing him. The guard places him in the back seat of a sedan and drives away. A few moments later, Menand is run down by the bus... at exactly eleven forty-six.

Mulder and Scully review the facts of the case. Nichols was taken into custody after the bus driver told police that he pushed Menand into the path of his vehicle. But Nichols tells authorities he was attempting to save Menand-as an unidentified old man had forewarned of his colleague's impending death.

The security guard who arrested the old man is found frozen to death. Scully concludes guard was somehow exposed to some sort of chemical refrigerant, as weather conditions are too warm to explain the corpse's frigid internal temperature. Mulder interviews Nichols at the police station. Nichols explains that he and Menand had been arguing because Menand threatened to go public with a claim that he had falsified data on a research paper.

A short time later, the elderly man kills Dr. Yonechi, a Japanese researcher, by pricking him with a metallic stylus. Mulder and Scully examine Yonechi's frozen corpse. Lab tests reveal that the doctor was injected with an unidentifiable chemical compound. The agents approach Nichol's girlfriend, Lisa Ianelli, who is also a researcher. She recognizes the chemical compound as a rapid freezing agent that Nichols had been engineering for years. But she points out that the chemical has not yet been invented. Lisa tells the agents that if Yonechi was injected with the chemical, he may not be dead. With Lisa's help, Scully and a team of medical personnel successfully resuscitate Yonechi. But his body temperature suddenly and rapidly begins to increase, until finally, he bursts into flames. Lisa realizes she made an error when she recommended that doctors remove Yonechi's body from a tub filled with yellowish fluid.

Lisa confesses that it was she who falsified the data to get the research grant (Nichols is in jail because he is covering for her). Those who would have figured out the truth-Menand and Yonechi-are now dead. Police receive a tip that the elderly man is living at a nearby hotel. Inside the elderly man's room, the agents discover a faded color photograph picturing Nichols, Yonechi and Lisa toasting champagne glasses inside the cryology lab. Mulder realizes the photo was taken five years in the future-on the day the researchers successfully synthesized the freezing compound. The elderly man is attempting to alter that future: when he failed to save Menand from being killed by the bus, he killed Yonechi. Mulder also realizes the elderly man is none other than Jason Nichols.

Lisa locates the elderly man and confronts him. The elderly man gathers the courage to inject her with the chemical. But Scully successfully resuscitates Lisa, and remembering the girl's words, immediately returns her body to the tub (to prevent the fire that killed Yonechi). Nichols confronts his elderly self in the computer mainframe room at the cryogenic lab, where the old man has erased all of Nichols' files from the computer. Nichols lunges at the old man, choking him. Mulder, unable to open the lab door, yells to Nichols. He tells him that Lisa is alive. The old man tells Nichols that "it's better that we never were." Wrapping his arms around his younger self, the old man bursts into flames. The fire consumes them both. Later, Lisa sets to work at cryonics lab, attempting to reconstruct the chemical compound.

Season 4 Episode #20
Small potatoes.

Doctors in Martinsburg, West Virginia, attend to a woman, Amanda Nelligan, as she goes into labor. When a nurse asks about the baby's father, Amanda tells her that the child's father is from another planet. When the baby is delivered, those in attendance gasp in horror when they see that the crying newborn has a four-inch tail.

Word of the strange birth is spread by newspaper tabloids, and Mulder and Scully travel to Martinsburg to investigate. During the drive, Mulder notes that five babies were born with vestigial tails over the course of three months -- all within a city of less than 15,000 people. Scully hypothesizes that the abnormalities may be attributable to ground water contamination or prescription drug interaction.

At the hospital, Amanda, a Star Wars fan, tells the agents the baby's father is Luke Skywalker. She recounts the tale of how Luke Skywalker came to her home and romanced her. With the assistance of a Health Department doctor, Scully determines that each of the five children born with tails share the same father. Mulder notes that all five women also shared the same fertility specialist, Dr. Alton Pugh.

When the agents arrive at Pugh's office, they discover several angry couples confronting the doctor about the births. As Mulder looks around the doctor's office, he encounters a janitor, Eddie Van Blundht, fixing a leaky sink inside an exam room and notices above his sagging pants a feint, roughly triangular scar at the base of the man's spine. Eddie tries to run, but is quickly apprehended and taken into custody. All of the women present swear that the only person they have had sex with has been their husbands. Later, a paternity test reveals that Eddie is the father of all five children. Scully hypothesizes that he may have used the tranquilizer Rohypnol to incapacitate his victims. Eddie, a homely man, responds defensively at the inference that the only reason a woman would have sex with him is if she was coerced.

While a sheriff's deputy is filling out his arrest record, Eddie suddenly changes form, metamorphosing into an exact duplicate of the deputy. Eddie strikes the astonished deputy on the head and makes his getaway. After questioning the deputy, Mulder concludes that Eddie impregnated four of the five women by making himself look like their husbands. The fifth woman, Amanda, was tricked into believing she was making love to Luke Skywalker.

The agents travel to the Van Blundht residence, where they meet Edward Sr. He claims he once performed as "Eddie the Monkey Man" and still has his tail intact. As they talk to him they realize the old man is, in fact, Eddie Jr. in a different form. Eddie suddenly runs out of the house and disappears into the neighborhood. After searching the house they discover the mummified body of the real Edward Sr. inside the attic. Scully's autopsy reveals an anomalous muscular structure beneath the surface of the corpse's skin. Essentially the man's skin was also a muscle. Mulder speculates that if Eddie inherited this same trait, it would explain his ability to change form. Meanwhile, Eddie metamorphoses once again -- this time into a duplicate Mulder. The real Mulder tracks him to a locker room at the hospital where Amanda Nelligan is staying. Suddenly, Eddie bursts through the ceiling, knocking him to the ground. He ties up the real Mulder and locks him inside the hospital's boiler room.

Pretending to be Mulder, Eddie returns to Washington with Scully, files a report with Assistant Director Skinner and closes the case. Later, the fake Mulder shows up at Scully's apartment with a bottle of wine. After spending the evening having relaxing conversation and relating in a personal rather than professional manner, Scully tells the fake Mulder, "I really feel like I'm seeing a different side of you tonight." The fake Mulder leans in close, and prepares to give her a kiss. Just as their lips are about to meet, the real Mulder kicks in the front door and interrupts them. Eddie slumps back on the couch, thwarted, and transforms back to his normal appearance and is taken into custody.

Season 4 Episode #21
Zero sum.

Jane Brody, a mail sorter at an overnight delivery company, sneaks into the female employee's rest room to smoke a cigarette. Without warning, hundreds of bees creep into the stall where Jane is sitting. When the young woman attempts to swat the insects so she can escape, the bees swarm and attack, stinging her to death.

An e-mail file containing photographs of the victim is sent to Mulder, but Skinner intercepts and deletes the file. Skinner then covertly erases evidence of the bee attack, and incinerates Jane Brody's body. Identifying himself as Fox Mulder, Skinner visits a police forensics lab in Virginia where he switches a vial containing Brody's blood with another identical container. As he is leaving, Skinner is approached by Detective Ray Thomas, the man who e-mailed Mulder photographs of Brody's body. Skinner tells the disappointed Thomas (who thinks he is talking to Fox Mulder) that the evidence does not warrant his further involvement in the case.

Mulder pays Skinner an unexpected visit. He states that someone has gone to great lengths to keep news of the bee attack from reaching him. He also reveals that Detective Thomas was found dead, the victim of an execution-style shooting. With Scully undergoing tests at a hospital for the treatment of her cancer, Mulder asks Skinner for his help in solving the mystery. Later that night, Skinner is approached by The Cigarette-Smoking Man. Skinner accuses him of murdering Detective Thomas. The Cigarette-Smoking Man counters that Skinner "failed to neutralize a potentially compromising situation."

Mulder discovers that someone stole Brody's body from a morgue and switched her blood sample at the police station. He also discovers that Thomas was murdered by someone using a government issue gun. Shortly thereafter, Skinner realizes his own weapon is missing. Skinner revisits the women's rest room where Brody was killed. He discovers part of a massive honeycomb inside the rest room wall, and brings a piece of the honeycomb to entomologist Peter Valdespino for analysis.

Mulder discovers that a bank surveillance camera captured a blurry image of someone talking to Detective Thomas shortly before he was murdered. He hopes the Bureau's Photo Unit can produce a clearer image of the man who he suspects is Thomas' killer. Using larvae taken from the honeycomb, Valdespino hatches more bees to identify the species. The insects unexpectedly swarm the entomologist, killing him. Mulder later discovers that Valdespino died from smallpox. He hypothesizes that someone has engineered a method of spreading the contagion using the insects.

Skinner questions Brody's co-worker, Misty Nagata. She reveals that a damaged overnight package was confiscated by other investigators working on the case. Students at an elementary school in South Carolina are attacked by a swarm of bees. Skinner tells doctors at a hospital emergency room that the children should be treated not for bee stings, but for smallpox.

Working from surveillance camera footage, the FBI photo unit produces a clear image of Skinner talking to Thomas shortly before his death. Outraged, Mulder accuses Skinner of working in conjunction with The Cigarette-Smoking Man from the very beginning. But Skinner insists he was framed.

Skinner again confronts The Cigarette-Smoking Man, firing several shots in anger. Afterward, The Cigarette-Smoking Man instructs Marita Covarrubias, in the company of Syndicate members, to tell Mulder whatever he wants to hear.

Season 4 Episode #22
Elegy.

Angie Pintero, the working-class owner of a bowling alley, tells one of his employees, a mentally-disturbed, compulsive man named Harold Spuller, to go home for the evening. Shortly thereafter, Angie discovers a badly-injured blond girl wedged inside a pinspotter carriage. The girl attempts to speak, but no words come out of her mouth. Angie notices police in a nearby parking lot and rushes outside to get help. He realizes a crowd has gathered around the dead body of the same girl he saw only moments earlier in the bowling alley.

Angie relates his bizarre tale to Mulder and Scully. Mulder suspects that Angie encountered the dead girl's ghost, a spirit that was attempting to communicate with the living for reasons unknown. Three similar encounters, and three similar murders, were reported in the area in as many weeks. The agents discover the words, "She is me" written on the bowling lane where Angie saw the spirit. But its meaning remains a mystery.

Detective Hudak tells Mulder and Scully that an anonymous caller phoned 911 with a message regarding Penny Timmons, one of the killer's victims. The caller claimed that Timmons' last words were "She is me." But Hudak notes the victim's larynx was severed, making it impossible for her to utter dying words.

The agents trace the source of the 911 call to a payphone at the New Horizon Psychiatric Center. Mulder notices one of the patients, Harold Spuller, avoiding his gaze. After viewing photographs of the murder victims, Scully comes to the conclusion that Spuller fits the killer's profile: a compulsive person consumed with the desire to organize, clean and reorder.

Scully uses a rest room to attend to a nose bleed. There she encounters the spirit of another blond girl. Moments later, Mulder relays word that the body of yet another victim was found nearby.

Mulder discovers Harold holed-up in a dimly-lit room accessible from the bowling alley. The walls of the room are covered with score sheets, including those of the victims. Mulder realizes that Harold met each of the murdered women at the bowling alley. Suddenly, Harold lapses into a strange seizure. From his point of view, he sees Angie's ghost standing behind Mulder. He rushes out of the room and makes his way to the bowling alley, where Angie lies dead, the victim of a heart attack. Mulder tells Scully that every person who saw the apparitions was about to die, implying that Harold may be next. Scully, who also saw a victim's ghost, is struck by the implication.

Harold is transported back to the psychiatric center. There, he is tormented by Nurse Innes, who ridicules his intellect and physique. Later, Mulder finds Innes lying on the floor, half-conscious. Innes claims Harold went berserk and attacked her. One of the other patients, Chuck Forsch, tells Scully that Nurse Innes was trying to poison Harold. Scully slowly realizes that Innes, not Harold, was responsible for the murders. When Innes attacks Scully with a scalpel, Scully draws her weapon and fires, striking her in the shoulder. Afterward, Scully tells Mulder that Innes has been ingesting Harold's medication, triggering violent and unpredictable behavior. She hypothesizes that Innes was out to destroy the love Harold felt towards the young women. Later, Harold's body is discovered in a nearby alley, the apparent victim of respiratory failure. But Scully suspects Harold died from what Innes took away from him.

Scully admits to Mulder that she saw the ghost of the fourth victim shortly after she was murdered. Later, Scully sees Harold's spirit sitting in the back seat of her car.

Season 4 Episode #23
Demons.

Mulder experiences a dreamlike vision, apparently a memory from childhood, in which he sees his mother and father reacting as if some terrible tragedy has entered their home. Mulder awakens in a motel room, sweating profusely, his hands and shirt stained with blood. He telephones Scully, who drives to the motel to offer assistance. Suffering from a mental blackout, Mulder cannot recall how he got to the motel. Scully discovers that two rounds were fired from his gun. She also traces a car parked outside Mulder's room to a David and Amy Cassandra. The agents travel to the Cassandra residence, where they speak with a house-keeper. Inside the home are dozens of paintings of a white clapboard house. Mulder realizes he was inside the home, but cannot remember why.

The housekeeper gives the agents the address of the home depicted in the painting. As Mulder approaches the dwelling, he is suddenly struck by a flashback in which he encounters a young Cigarette-Smoking Man inside his parent's home. When the seizure subsides, the agents walk inside the cottage, where they find the dead bodies of David and Amy Cassandra.

Blood from both victims is found on Mulder's shirt. Detective Curtis places Mulder under arrest. But a toxicology report reveals traces of the anesthetic Ketamine in Mulder and Amy Cassandra's blood. Scully realizes the drug could account for Mulder's memory loss. A short time later, Michael Fazekas, an admitting officer, steps inside a bathroom at the police station and shoots himself in the head. Scully discovers a small scab on the man's scalp, similar to one found on Amy's hairline. Detective Curtis reveals that Fazekas was a believer in UFOs. Inside Fazekas' apartment, Scully discovers a UFO magazine featuring a photograph of Amy, who believed she was an alien abductee.

A forensics report reveals that the blood spatter pattern on Mulder's shirt does not correspond to the point of entry detail. Curtis concludes the Cassandras died as the result of a murder-suicide. Further research reveals that Amy had been seeing Dr. Charles Goldstein, a psychiatrist, in an effort to recover suppressed memories. Goldstein admits he used unconventional therapy to stimulate electrical impulses in the brain.

Mulder suffers another seizure. During the attack, he experiences a vision in which a young Cigarette-Smoking Man pulled Mrs. Mulder close to him, as if to kiss her. Mulder and Scully drive to Mrs. Mulder's Greenwich home. There, Mulder confronts his mother. He accuses her of lying to him about having been forced to choose Samantha over him. He also accuses her of being unfaithful to his father. Mrs. Mulder angrily denies the allegations. Mulder storms out of the house and drives off.

Mulder pulls a gun on Dr. Goldstein and forces him to finish his treatment--to make him relive (what he believes to be) to his past. Goldstein drugs Mulder, then slowly lowers a spinning needle towards his hairline. Police arrive at the scene and place Goldstein under arrest, but Mulder's whereabouts are unknown. The psychiatrist tells Scully that Mulder left his office "to exorcise his demons." Scully finds him at the house in Quonochontaug, balled up on the floor, a gun in his hand. Jolted by seizures, Mulder aims his gun at Scully. She attempts to convince him that the powerful hallucinogen injected into his body has affected his mind and that his visions, his apparent memories, cannot be trusted. Mulder fires a shot, but the bullet shatters a wall mirror behind Scully. Breaking down into tears, Mulder lowers the weapon. Scully's fear changes to sympathy as she comforts her partner.

Season 4 Episode #24
Gethsemane.

Scully enters Mulder's apartment, where a group of detectives and forensic technicians are waiting. Detective Rempulski introduces himself, then pulls back a sheet draped over a body lying on the floor. Scully positively identifies the victim. Later, Scully appears before a group of FBI officials led by Section Chief Scott Blevins. During the meeting, Scully recounts how, four years earlier, Blevins assigned her to a project known as The X-Files. She states that the purpose of the current meeting is to report on the illegitimacy of Mulder's work.

In flashback, a pair of anthropologists, Arlinsky and Babcock, are flown by helicopter to a snowbound camp at the base of a mountain. Accompanied by a guide, the pair make their way up the steep terrain. Upon reaching the summit, the men enter a cave where the body of a gray alien is perfectly preserved in ice.

A group of guests gather at Mrs. Scully's house for a dinner party. Amongst the attendees are Dana's brother, Bill Scully, Jr., and a Catholic Priest, Father McCue. Scully realize McCue was invited by her mother for the purpose of discussing her faith at a time when Scully's health is at great risk due to her cancer. After dinner, Father McCue and Scully briefly talk about her drifting from the church before their discussion is interrupted by a phone call from Mulder. He has received information about a something that was discovered in Canada.

Mulder arranges for Scully to meet he and Arlinsky at the Smithsonian. Arlinsky claims that, based upon ice core samples taken from the scene, the alien body is some two hundred years old. He asks for the agents' assistance in verifying the alien remains. Mulder and Arlinsky fly to the base camp, which is eerily deserted. Unbeknownst to them, a mysterious assassin armed with a shotgun pistol has murdered the Summiteers. Upon reaching the summit, the men discover the bodies of Babcock and a foreman. Inside the cave is a rectangular hole where the alien body had been entombed. Later, Babcock, injured but alive, tells the pair that he buried the alien body beneath his tent.

Meanwhile, Scully and lab scientist Vitagliano examine ice core samples taken from the cave. Later that night, Scully returns to the Bio Lab, where she is assaulted and thrown down a flight of stairs by an unidentified attacker. Agent Hedin matches fingerprints found on the stairwell to a Michael Kritschgau, who works for the Pentagon's research division. After viewing a personnel file, Scully positively identifies Kritschgau as her attacker. Later, she confronts Kritschgau inside a parking garage and places him under arrest. But Kritschgau warns that if he is taken to jail, the same people who gave Scully cancer will kill him.

Mulder and Arlinsky transport the alien body to a warehouse where an autopsy can be performed. Scully contacts her partner at the warehouse and arranges a meeting so he can hear Kritschgau's story firsthand. Soon afterward, the assassin, Ostelhoff, shoots and kills Arlinsky and Babcock at the warehouse. Meanwhile, Kritschgau, who claims to have run the Department of Defense's agitprop arm, tells the agents that the government has been orchestrating an elaborate hoax to divert attention away from itself. The alien corpse, Kritschgau claims, was forged from bio-materials and frozen into place over the course of a year. He insists Mulder was only meant to see the alien--to make him believe the lie. Mulder counters that it is Kritschgau who is the liar. But when Mulder returns to the warehouse, he discovers the dead bodies of Arlinsky and Babcock--and the alien specimen missing. Shortly thereafter, Scully tells him the men behind the hoax gave her cancer all in an effort to make him a believer in their lies. Mulder is stunned by the revelation.

Back in the current day, Scully tells FBI officials that she received a phone call from the police department asking her to identify a body inside Mulder's apartment. Struggling to maintain composure, Scully reveals that Mulder died of an apparent self-inflicted gunshot wound to the head.