The ritualistic murder of a teenager in a small town gets Mulder and Scully caught up in a secret occult practice within the local school's PTA and a substitute teacher with strange powers.

Mulder and Scully travel to Gibsonton, Florida, a town built and populated by circus and sideshow performers to investigate the death of Jerald Glazebrook, The Alligator Man. While searching for leads on the killer, the agents come across many bizarre characters including the local sheriff who was once known as Jim Jim, the Dog-Faced Boy.

Mulder and Scully investigate a series of human and cattle deaths by lightning and are led to a teenage boy who is the only survivor out of five people recently hit by lightning strikes.

Mulder seeks the help of a woman who he believes has a special connection with a young girl who has recently been kidnapped by the same man who held her captive many years earlier.

Widespread panic is caused in a small community after numerous deaths are linked to killer cockroaches, and a government agricultural agency is discovered to have set up a secret experiment involving insects.

A serial killer is captured after a three year manhunt, and he claims an evil spirit is responsible for the crimes. When the killings continue as he sits in jail, Mulder's battle with a former colleague gets more heated when he suggests that something more paranormal may be involved.

Mulder pursues Krycek (unaware of the alien that has taken over his body) to get back the DAT tape containing the MJ documents. Meanwhile, the shooting of A.D. Skinner uncovers evidence that could lead Scully to her sister's murderer.

The unearthing of an ancient Ecuadorian Amaru urn and its removal to America despite protests leads to a series of deaths linked to a shaman spirit released by the urn.

Mulder and Scully investigate a series of disappearances and attacks around a lake where Mulder believes that the local legend about a lake monster may be all too real. Frustrated Scully insightfully confronts Mulder about the futility of their work on the X-Files.

A baby is found buried alive in shallow ground and appears to have birth defects resulting from generations of inbreeding, leading Mulder and Scully to a reclusive family who have a history of inbred children.

After a doctor loses control and kills a patient on the operating table, Scully hypothesizes that it's linked to work-related stress, while Mulder is convinced of a more sinister reason. After he finds a link between the victim and the four witches Sabbaths, he suspects that a nurse may be practicing witchcraft.

Mulder is given a tip about potentially dangerous paramilitary operations on the U.S. soil but during the sting operation is surprised to find out the identity of his mysterious informant - it turns out to be Alex Krycek. Suspicious about his true motives, Mulder reluctantly follows the information provided by Krycek. However, soon he discovers a much bigger conspiracy which takes him to a gulag in Tunguska, Russia where prisoners are being used for experiments involving a substance of alien origin.

After the body of a decapitated EMT disappears from the morgue and an identical man starts work at the same hospital, Mulder believes that the man has the ability to regrow parts of his body, including his head. The agents soon discover that Betts' body is riddled with cancer and he is able to live in that condition but needs to feed on cancerous tumors to keep up his strength.

After a Jewish man is murdered in a Jewish community, his killers are murdered, too. Mulder and Scully have to determine whether someone is exacting vengeance or larger forces are at work.

Mulder is arrested for investigating the plane crash and interfering with a military operation, while Scully is caught in an attempted assassination of Corporal Frish which claims the life of Agent Pendrell. Scully bails Mulder out of prison, and they go to Max Fenig's trailer to find out why he was on the plane. Mulder finds evidence of alien technology and boards a plane with it, but the plane is intercepted mid-flight and it disappears. Mulder is again left with nothing.

After a swarm of bees mysteriously kill a postal worker in an enclosed restroom, Assistant Director Skinner covers it up by destroying the evidence. In order to complete the task he poses as Agent Mulder, however his deception backfires. When Mulder finds out and confronts him, Skinner reveals that he is working for the Cigarette-Smoking Man in order to obtain a possible cure for Scully's cancer.

Covered in blood and suffering from amnesia, Mulder pieces together the events of the last few days, but the trail leads to a double murder that appears to have been committed with Mulder's weapon.

Scully helps Mulder fake his own death in order for him to go undetected through the Department of Defence and find out the answers to his new questions about the government hoax concerning the existence of extraterrestrial life. Meanwhile, at a joint FBI/DOD inquiry, Scully's attempt to drive out the Conspiracy's informant is halted as her cancer takes a bad turn.

The Cigarette-Smoking Man helps Mulder to obtain Scully's cure and also lets him see his real sister who doesn't turn out to be as happy to see Mulder as he would've liked. In return for this, the Cigarette-Smoking Man asks that Mulder quit the FBI and work for him in the Syndicate where he could have power and respect which Mulder turns down, deciding to stay on the side of justice. While Scully's cure appears to have worked, the Cigarette-Smoking Man faces his own enemies and disappears, presumed dead.

Set in 1989, the story of the founding of The Lone Gunmen is finally told as we see how a straight-laced federal employee, a sex mad AV expert, and a nerdy computer hacker meet Susanne Modeski, a strange woman with evidence of a government conspiracy. When their plan to expose the conspiracy fails and Susanne is captured by a group of men-in-black, led by none other than X, they soon become a paranoid group of government watchdogs.

DNA testing on Emily reveals that she is actually Scully's daughter and Mulder comes to assist her and to find out where and how the girl was born while Scully tries to help Emily with her own serious illness, a rare form of anemia.

Master of Horror Stephen King's first effort at an X-File sees Scully's well deserved vacation going terribly wrong and landing her in a small Maine town where one of the residents is believed to be a witch, and her autistic daughter's doll has frighteningly evil powers.

Mulder and Scully meet Cassandra Spender, a woman who claims to be a multiple abductee and wants to deliver a positive message about the aliens. Mulder's new found disbelief in extraterrestrial activity is enhanced while Scully forms a special bond with the woman. A series of group attacks against abductees take place and the shadowy Syndicate believes that a rebel alien resistance is attempting to destroy all their work.

Mulder and Scully try to get answers out of a stubborn blind woman found at a murder scene who may have the ability to look through the killer's eyes in her mind.

Mulder is less than thrilled when an Office of Professional Conduct board refuses to reassign him and Scully to The X-Files and even more so when he learns that Agent Spender and Agent Fowley have become their successors. When Gibson Praise reappears and comes to them for help, Mulder and Scully attempt to continue their quest undercover despite having fewer friends and less access and protection than ever before.

While being detained near the famed "Dreamland" Area 51, a strange craft flies overhead and Mulder swaps bodies with an Area 51 "Man-in-Black". While the other agent has fun in Mulder's body, Mulder himself finds it difficult to fit into someone else's life, especially a shadowy one. Mulder contacts Scully about the body swap and tries to get her the flight data recorder from the UFO test flight, but his alter ego uses Mulder's FBI persona to have him arrested.

Mulder is thrown in jail at the Area 51 compound but is released when it is discovered that the flight data recorder he stole was a fake. Scully comes to her senses and realizes that the Mulder she sees isn't who he really is and heads back to Nevada to help the real Mulder. Meanwhile, the mechanism that caused the body swap is rapidly snapping back, undoing everything in its wake, and Mulder and his alter ego must race to put themselves back where they belong.

Strange weather phenomena in a small town leads Mulder to believe that a weatherman's deep emotions and unspoken love toward his workmate are becoming real in the form of snow and tornadoes.

While the Cigarette-Smoking Man recites to an unseen listener everything about the work of the Syndicate involving a global conspiracy in cooperation with an alien species, Cassandra Spender reappears and is pursued by the scientists who would rather kill her than keep her alive. Cassandra runs to Mulder's apartment and demands that he shoot her because she is the culmination of 50 years work - a living alien/human hybrid - and colonization will begin if the aliens find out about her.

A woman is forced to relive the same day over and over as she tries to prevent Mulder and Scully from being killed by her boyfriend during a bank robbery attempt. As the events restart again and again, Mulder's sense of Deja-vu grows stronger.

A writer living next to Mulder becomes obsessed with Scully and confesses to her that he is using her for a character in his novel. Scully finds herself strangely drawn to him even though he is now the prime suspect in the murder case that she and Mulder are investigating.

When the bodies of a couple who have been missing for less than a week are discovered to have been reduced to bone, Mulder suggests that recent paranormal phenomena in the area may have caused the accelerated decomposition.

While Scully travels to Africa to piece together the meaning of the symbols on the spaceship beached on the Ivory Coast, Mulder is imprisoned by his own frenetic brain activity. He manages to get a message to Skinner who finds Kritschgau, and together they try to understand what is happening to Mulder before it is too late.

A monster who feeds on human brain matter tries to lead a normal life, but he soon cannot control his feelings of hunger.

Snakes are killing the unrighteous, but Mulder and Scully doubt that this is a case of divine intervention.

After arresting the murderer of Amber-Lynn LaPierre and discovering a mass grave site containing the bodies of dozens of missing children, a man comes to Mulder and claims to have had visions of other victims who aren't buried at the site. Despite Scully's objections, he takes Mulder on a journey which reveals what truly happened to his sister.

Mulder and Scully suspect that hexcraft is the source of threats against a doctor's family.

While protecting a man due to testify against the Morley cigarette company, Skinner is horrified when the witness dies mysteriously. What the agents soon discover is that a new brand of cigarette has a dangerous secret.

Mulder and Scully return to the town of their first X-Files investigation where a UFO has crashed in the forest. The Cigarette-Smoking Man arranges for Krycek to be released from prison in order for him to make contact with the aliens and begin rebuilding the "Project", while Scully's health appears to be taking a turn.

Newly appointed Deputy Director Kersh organizes a manhunt for Mulder and assigns Agent John Doggett to head the team. Scully and Skinner go along with the investigation but are warned by Kersh that they will be fired if anything is said about aliens. Scully, along with the Lone Gunmen, surmise that the Bounty Hunter is trying to erase all evidence of abductions, and they realize that he may be going after Gibson Praise, who is now living at a school in Arizona. Agent Doggett comes to the same conclusion and his team race Scully and Skinner to the school where they find Mulder trying to kidnap Gibson.

As the search for Mulder intensifies in the Arizona desert, Gibson Praise leads Scully to believe that she is truly closer to her target. Meanwhile, A.D. Kersh informs Agent Doggett that he has been assigned as Mulder's successor on the X-Files.

Doggett comes upon an old case that Mulder kept secret from Scully and he follows up the investigation, hoping to find a possible connection to Mulder's disappearance.

When Scully and Doggett are contacted by a man who claims his wife was murdered shortly after giving birth to an alien baby, Scully digs deeper into reports of alien fertilization on humans, and she begins to question her own pregnancy and its conception.

When Teresa Hoese (the woman Scully and Mulder met the previous spring in Oregon just before Mulder was abducted) is found in a desert after enduring alien testing, Doggett alerts Scully that this could have something to do with Mulder and his whereabouts. Skinner joins them and they travel to the hospital where Teresa is clinging to life by a thread, and Scully realizes that this is exactly what's going on with Mulder.

Mulder and Doggett join forces to investigate the arson attack on a genetics lab where one of the doctors suspected of experimenting with alien impregnation is killed. They encounter Billy Miles, who has been changed into an alien replicant after his recent abduction and is attempting to erase evidence of the tests. When a woman helping Scully out at home is found to be a part of the conspiracy, the agents, along with Monica Reyes and Alex Krycek, know they must protect Scully and her baby from Billy Miles and get her out of the city.

Mulder, Doggett and Skinner attempt to fight off the alien replicants, and they find a connection to the conspiracy that leads into the FBI while Reyes and Scully head to a remote farm to safeguard the birth of Scully's child.

Agent Doggett investigates the death of an EPA official after his car is forced off a bridge by a woman he picked up. He asks for assistance on the case from Scully, who has returned to her teaching position at the FBI Academy in Quantico.

When a stunt on a local cable reality show goes horribly wrong resulting in a man's death, Doggett and Reyes investigate. But when flies pour out of the victims eye sockets, they find themselves relying on Scully's expertise and ask her to join the investigation.

Agent Reyes takes the lead while investigating an X-file case, surrounding a man found skinned alive after having visions of seeing other people appearing skinned alive. Reyes calls on Scully's expertise to help on the investigation, which pays off when Scully finds a link to a case from 1960.

When pieces of the spaceship beached in Africa resurface, the conspiracy within the FBI attempts to hide the information from the X-Files, especially the one person for whom the pieces have a special significance - Scully. When Doggett and Reyes discover that Scully and her child have been put in great danger, they race to protect her and William from the evil forces pursuing him, and Scully is forced to take drastic measures to protect her child.

After a car accident, Reyes finds herself in a very gray area, while Doggett desperately denies doctors' diagnoses about his partner, who witnesses a strange disappearance.

When an FBI cadet with amazing profiling skills approaches Doggett, Reyes, and Scully with a lead on a suspect in a series of recent murders, he claims the same killer is responsible for the death of Doggett's son. The agents find themselves wondering if his knowledge of the deaths is because of his obsession with the cases he has studied at Quantico, or if he is in some way involved in the murders.

After not knowing Fox Mulder's whereabouts for the last year, A.D. Skinner and Agent Scully learn he's being held for the murder of a military man he couldn't possibly have killed: Knowle Rohrer, one of the government's secret super-soldiers. With Skinner acting as Mulder's defense, people who Mulder has dealt with during his last nine years as an FBI agent testify on his behalf. But the military tribunal isn't interested in the truth.

When an unexpected person comes to Mulder's rescue, Mulder refuses to slip north over the border to safety. Instead, he heads southwest to the Anasazi ruins of New Mexico seeking a mysterious wise man who the Indians call "The Keeper of the Truth".