Mulder and Scully learn that they aren't the only ones desperately searching for their long-lost son, William. The very fate of the world may depend on the outcome.

A chilling secret is revealed when an old friend reaches out to Mulder and Scully in a seemingly impossible way.

Mulder and Scully investigate a case involving several deaths where the victims previously reported encountering their own doppelgangers. The clues lead to a pair of fraternal twins playing a dangerous game telepathically.

Exploring the idea of The Mandela Effect, in which large groups of people remember an alternate history, Mulder and Scully find out how the X-Files themselves may really have originated.

When a pair of teenage girls attack one another, each believing the other to be a monster, Mulder and Scully find that their investigation could possibly lead back to their long-lost son, William.

Skinner goes AWOL when his past comes back to haunt him. As Mulder and Scully try to track him down, their growing mistrust of him reaches its apex.

In a world of ever-increasing automation and artificial intelligence, Mulder and Scully find themselves targets in a deadly game of cat and mouse.

Mulder and Scully suspect that darker forces are at play as they investigate a brutal animal attack on a little boy in Connecticut.

While investigating human organ theft, Mulder and Scully uncover a mysterious cult consumed with macabre rituals.

Mulder and Scully rush to find an on-the-run William while the Cigarette Smoking Man pushes forward with his ultimate plan.