A newly married FBI agent is drawn into an illicit affair with his star informant, resulting in a scandal that endangers all his investigations.

Two streetwise undercover detectives bust criminals in their red-and-white Ford Torino with the help of a police snitch called Huggy Bear.

They were the perfect strangers, assembled to pull off the perfect crime. Then their simple robbery explodes into a bloody ambush, and the ruthless killers realize one of them is a police informer. Now, they have to figure out which one is the snitch.

After a botched bank robbery, the gang meets up in a warehouse, only to suspect that one of them is really a cop.

Two agents from vastly different backgrounds join forces to solve cases the FBI labeled an unexplained. Both are determined to uncover hidden truths; one searching for otherworldly answers, the other for more earthbound scientific explanations. Together they will make discoveries neither could have ever imagined.

Scully faces a life-threatening challenge that seems tied to her alien abduction, and Mulder is imprisoned in a Russian gulag. Suspicions about the U.S. government mount as evidence indicates there may be a cover-up over a biological weapon with alien origins. New information comes to light that may bring clues about the fate of Mulder's sister, and shocking revelations about the Cigarette-Smoking Man light up.

Paired with the skeptical Doggett, Scully relentlessly keeps up the search for Mulder, never relinquishing hope that he is alive. Ultimately, Mulder₂s miraculous resurrection proves her right. Meanwhile, numerous reptilian creatures shape shift into human forms, including people familiar to Scully and Doggett, which makes them question who to trust. Clues about a tragedy from Doggett's past emerge as the mysteries of alien life and the paranormal...

As the third season begins, Mulder is missing and assumed dead; although Scully experiences a vision in which he is still alive. Yet, even as the partners are reunited, each must deal with additional personal loss, both enduring tragedies that ultimately serve to strengthen their connection to each other. Soon, they find themselves depending on that bond as familiar foes resurface and preconceived notions are shattered.

As the second season begins, the X-files have been shut down and Mulder and Scully are separated. Scully finds herself teaching classes at the FBI Academy, while Mulder is assigned to surveillance duty. With Agent Alex Krycek as his new partner, and the mysterious X as his new source of information, Mulder struggles to keep his search for the truth alive. But ironically it is Scully who experiences with the close encounter Mulder has longed for, taking...

Scully must put her faith in the Cigarette-Smoking Man, in hopes that doing so will bring her knowledge about the cure for all human disease. Mulder finally learns the truth about the disappearance of his sister Samantha. But after he and Scully return to Oregon, to the site of their first case together, he himself disappears.