While being detained near the famed "Dreamland" Area 51, a strange craft flies overhead and Mulder swaps bodies with an Area 51 "Man-in-Black". While the other agent has fun in Mulder's body, Mulder himself finds it difficult to fit into someone else's life, especially a shadowy one. Mulder contacts Scully about the body swap and tries to get her the flight data recorder from the UFO test flight, but his alter ego uses Mulder's FBI persona to have him arrested.

Mulder is thrown in jail at the Area 51 compound but is released when it is discovered that the flight data recorder he stole was a fake. Scully comes to her senses and realizes that the Mulder she sees isn't who he really is and heads back to Nevada to help the real Mulder. Meanwhile, the mechanism that caused the body swap is rapidly snapping back, undoing everything in its wake, and Mulder and his alter ego must race to put themselves back where they belong.

Assistant Director Kersh tries to tear Scully and Mulder apart when he partners Scully with a New York agent investigating Alfred Fellig, a freelance police photographer who conveniently shows up to document the scene of a death as soon as it happens.

While the young hotshot agent is convinced that Fellig is murdering the people, Scully has other (paranormal) theories.

On their first official case back on the X-Files, Mulder and Scully go undercover as a married couple at a prestigious planned community where several residents have recently disappeared after failing to comply with the rules and regulations.

Scully frantically searches for a way to help her ailing partner without having anyone to turn to for help, while a catatonic Mulder's dreams lead him away from his mission and the X-Files to a place which he believes is a better life.

A young girl inexplicably disappears from her home, and Mulder requests the case even though it is a full FBI matter, not just an X-File. When Mulder takes some outrageous leaps to convince the girl's parents that she will be found, Scully fears that Mulder is becoming too personally involved with the case because of his sister's abduction.

A Los Angeles police officer who is being filmed for the show COPS is attacked by a strange monster and Mulder and Scully are investigating the case. Scully is wary of having their faces put on national television but Mulder welcomes the publicity.