A spate of deaths, in which the victims were plagued by their own doppelgangers, lead Mulder and Scully to a pair of twins playing a dangerous game.
In a small rural Virginian community event, Arkie Seavers appears to see himself in the back of the crowd. He flees the event, only to have his doppelgänger grab the wheel and drive him into a tree.
Fox Mulder (David Duchovny) discovers the Seavers case and compares this incident to a number of people who have tried to kill themselves after claiming they saw someone who looked exactly like them. Dana Scully (Gillian Anderson) thinks Arkie is lying, but Mulder is more inclined to believe. The agents meet with a barely-alive Seavers and discuss his experiences from last night. Mulder and Scully meet a patient at a psychiatric hospital with dissociative identity disorder named Judy Poundstone (Karin Konoval). Her room is filled with games of hangman, which she claims she plays with her brother, Chucky, who lives across town.
After being placed into a cell, Arkie's doppelgänger appears in the cell with him, presumably killing him. Mulder and Scully check into the St. Rachel Motel to sleep for the night. He comes to her in the middle of the night to reveal Arkie’s death. Scully argues that it is a suicide, while Mulder and attorney Dean Cavalier don't believe so.
Mulder finds the irascible Chucky (also Konoval), living by himself, in a similar setup as Judy. His walls are filled with hangman games. Meanwhile, Scully meets with “Demon Judy”, an evil alter ego, who seems to be flinging "Dookie!" brand chocolate pudding at the cell door. One of the nurses point out that both of the Poundstone parents hung themselves. Scully tries to get more information out of Judy, but is tormented by this new nemesis.
Chucky and Judy began playing the game again, this time targeting Dean Cavalier. First, Dean sees his double and goes to tell Scully and Mulder. The agents tell him to stay calm and hide away all weapons of harm. Dean ventures to his home and tosses multiple equipment onto the floor. He realizes that the room is filled with swords. Dean accidentally cuts himself with one of the blades. Before he can aid his wound, he sees his double again. The agents arrive to find Cavalier with his head cut off.
Back at the motel, Mulder sees his double in the bathroom and freaks out. Mulder races to confront Chucky as Scully goes to stop Judy. On her way to the hospital, Scully sees her double in the backseat of her car, but stays calm, calling the figure a "manifest psychic ideation." It turns out that the twins are fighting each other, not being able to decide which agent to hang. Before the agents can interrupt their game, the siblings both "hang" each other. On Chucky's wall, Mulder finds two hangman games for "Mom" and "Dad."
- Karin Konoval had previously appeared as Mrs. Peakcock in the season 4 episode "Home".
- It was mentioned by Gillian Anderson and Kevin Hooks on Twitter with multiple references.
- Mulder and Scully will sleep together. 
- Series creator Chris Carter tells TVLine exclusively that Robert Patrick who portrayed Agent John Doggett was actually slated to appear in one of Season 11’s early installments. “I actually wrote him into an episode,” Carter reveals. “But then I found out he wasn’t going to be available to us because of Scorpion so I had to write him out of the episode… Scorpion is his first priority.”
- Karin Konoval as Little Judy Poundstone and Little Chucky Poundstone
- Benjamin Wilkinson as Dean Cavalier
- Jared Ager-Foster as Arkie Seavers
- Denise Dowse as Dr. Babsi Russel
- Lossen Chambers as Nurse Peggy Easton
- Alison Araya as Nurse Vickie Easton
- Elizabeth Lavender as Attractive Waitress
- Thabo Ketshabetswe as Guard
- Rhett Spenceras as First Dude
- Kathryn Kirkpatrick as Receptionist
- Mulder counts Scully's age in "dog years". He did the same thing in Tempus Fugit.