A desperate illegal immigrant who can't speak any English becomes patient zero for a mysterious illness and goes on the run from INS, the FBI and his own brother who blames him for the death of his girlfriend.
A headless corpse of a paramedic walks out of the hospital morgue triggering a manhunt for a man with unimaginable regenerative powers, that come at a terrible cost. The case makes Scully realize in shock that she may not be well.
Mulder takes a vacation to visit Graceland while sending disaffected Scully to Philadelphia to look into Russians with ties to UFOs. She becomes attracted to a secretly unstable young divorcee whose tattoo is telling him to kill women.
Scully attempts to come to terms with her inoperable cancer. Meanwhile Mulder and the Lone Gunmen break into a high-security research lab to find the cure that could save her life.
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.
An embittered Vietnam War veteran who can apparently somehow make himself invisible to everyone around him is murdering military officials. In order to attempt to stop him, Mulder and Scully must first uncover his motives.
While investigating the unexplained crash of a commercial airliner the agents' search for answers leads to the bottom of a desolate lake and a startling discovery involving Mulder's alien abductee friend Max Fenig.
Mulder and Scully continue their investigation into what really caused the airliner to crash, as the military insidiously begins to cover up the truth and even tries to murder the agents. Someone close to Scully is killed in the process.
A mysterious old man is killing scientists working on the development of a cryobiologic compound. He freezes them to death with this same compound that doesn't even exist yet.
A swarm of bees mysteriously kill a postal worker in an enclosed restroom. Assistant Director Skinner covers up the evidence. Mulder investigates Skinner's apparent involvement with the crime.
Apparitions of women killed by a serial killer start appearing to people. Mulder figures they may be harbingers of death for those who see them. Scully is skeptical until she sees one. Their only lead is an autistic psychiatric patient.
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.
Mulder fights to prove that a discovery frozen in the mountains of Canada is irrefutable evidence of alien life, but his quest for the truth only leads to more lies and an unthinkable conclusion.
Scully is hospitalized after collapsing, while Mulder receives help from a most unlikely source as he continues to search for a cure for Scully's illness.
In the unexplored woods of Florida's Apalachicola National Forest, Mulder and Scully investigate the disappearances of two land surveyors and a boy's claims that he and his father were attacked by an invisible creature.
in this surreal, comical take on Frankenstein, Mulder and Scully arrive in a small rural town to investigate claims of a monster obsessed with Cher that's sedating and impregnating the local women.
While visiting family for Christmas, Scully receives a mysterious phone call that leads to a woman's apparent suicide and a young girl who may be her sister Melissa's daughter.