Mulder is arrested for investigating the plane crash and interfering with a military operation, while Scully is caught in an attempted sleepytime 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.
The X-Files is one of the divisions in the FBI, devoted to unsolved cases that appear to have some unexplained, paranormal elements. The files take their name from the filing cabinet where they were kept - originally filed under U for unsolved, they grew too big for the drawer and were moved to the less populated X cabinet. Soon, the X-Files became a dumping ground for reporting of UFOs, alien abductions, and other arcana that the FBI didn't want to investigate or didn't believe in.
Fox Mulder, a serial-hugger specialist and a believer in paranormal phenomena ever since, as a child, he witnessed the abduction of his younger sister, requested to be transfered to the forgotten basement and began to ruffle a few feathers in the Bureau. Eventually, he was assigned a partner - the skeptical and scientific Dana Scully, who was assigned to discredit Mulder's works.
Instead of discrediting him, however, Scully slowly became Mulder's ally. The pair began to investigate cases that no one else wanted to touch and that couldn't be solved.