4-D (The X-Files) - Plot

Plot

Monica Reyes (Annabeth Gish) monitors Erwin Lukesh, a suspected serial killer who cuts out his victims' tongues. While pursuing him, Reyes goes into an apartment building and is attacked by Lukesh with a razor. John Doggett (Robert Patrick), observes the pursuit electronically and hears a scream. He rushes to help Reyes and finds her dying, her throat cut. Doggett chases Lukesh into an alleyway, where the killer seemingly vanishes. Lukesh then appears behind Doggett and fires at him with Reyes' gun.

The setting then changes; Doggett arrives at Reyes' new apartment with a housewarming gift. Neither seems to be aware of the previous events. Reyes than receives a phone call from Walter Skinner (Mitch Pileggi), who informs her that Doggett has been shot and is being taken to the hospital. Reyes tells Skinner that Doggett is in her apartment, but then finds that he has vanished. When she arrives at the hospital, Reyes learns that Doggett was shot with her gun. Reyes is questioned by the FBI, insisting that Doggett was with her at the time of the shooting. Meanwhile, Lukesh watches the interrogation and identifies Reyes as the shooter.

Doggett regains consciousness, but is breathing with the help of a respirator. Meanwhile, Lukesh goes to his apartment where he lives with his disabled mother. As he prepares to fix her lunch, he goes to his freezer and pulls out a bag containing a human tongue. Reyes performs a background check on Lukesh, and becomes convinced that he is in fact responsible for the shooting. Reyes goes to Doggett, and through a computer setup that enables him to tap out words, Doggett tells her that Lukesh shot him but that Doggett also saw her with her throat cut.

Lukesh then returns to the alleyway where Doggett was shot and vanishes. Based on the contradictory evidence, Reyes concludes that Lukesh can travel between parallel universes in order to kill. She also concludes that the unharmed Doggett disappeared because two versions of the same person cannot exist in the same universe. Skinner questions Lukesh, who becomes agitated when his mother is mentioned. Noting this, Skinner decides to hint that his mother will be questioned, which leads Lukesh to become more uncomfortable. Lukesh returns home to find his mother has found the gun with which he shot Doggett. After she threatens to talk to the FBI, Lukesh kills her.

Doggett tells Reyes that, in order to resolve the situation, she must turn off his respirator and allow him to die, but she refuses. Suspecting that Lukesh plans to kill Reyes next, Skinner convinces Reyes to go back to her apartment while he, Scully, and Follmer monitor her. She returns and is attacked by Lukesh. The team rush to her aid and Follmer shoots Lukesh in the head, killing him. Reyes then returns to the hospital, closing her eyes as she shuts off Doggett's respirator. As she opens her eyes, the scene changes back to her apartment at the moment Doggett had disappeared earlier. Reyes, stunned and fighting back tears, embraces Doggett as he, evidently unaware of any of the previous events, asks her what is wrong.