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 it.
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.
