A mysterious Plain-Clothed Man alerts Mulder to a pair of multiple-homicides in which the killers suddenly became delusional. Mulder is unsure who the informant is working for, but he nonetheless follows up on the tip. He and Scully visit a psychiatric hospital, where Joseph Patnick, one of the mass murderers, suddenly goes berserk while watching television. The agents meet with Dr. Stroman, who theorizes his patient might be suffering from a delusional syndrome.
     The agents search Patnick's home looking for clues. While combing the house, Mulder and Scully locate row upon row of video cassette tapes containing cable news broadcasts. Back at the motel, Mulder views hours of the news footage but is unable to formulate a link between the broadcasts and the murders. Scully, however, cites recent studies linking television violence to violent behavior. Mulder dismisses the connection.
     Out of curiosity, Scully views the rest of the video tapes. Late that night, she sees Mulder and The Cigarette-Smoking Man meeting in secret in a car parked outside the motel. The next day, the agents receive word regarding yet another strange murder. This time, a housewife suddenly beat a neighbor to death. The killer, Mrs. Riddock, told authorities that her husband was having an affair with a blonde woman in a hammock in their backyard. In reality, Mrs. Riddock attacked and killed her next door neighbor, who was resting in a hammock with a Golden Retriever. The agents search Riddock's home and uncover a large pile of VHS cassette tapes. Mulder spots a cable technician working on a utility pole nearby. When the technician drive off, Mulder climbs the pole and removes a video trap device. He brings it to the Lone Gunmen for analysis.
     Meanwhile, Scully grows more and more suspicious about Mulder's activities. While speaking with Scully over the telephone, Mulder notices her paranoia and drives back to the motel. Believing she is being attacked by unknown intruders, Scully opens fire, narrowly missing her partner. She then runs off.
     The Lone Gunman confirm Mulder's theory that the device somehow induces violent behavior. Using different colors, it acts as a sort of mind control. Mulder, who is red-green color blind, realizes why he was not affected.
     Mulder receives word that Scully's body may have been located. Before he reaches the morgue, the Plain-Clothed Man warns him to concentrate on finding the parties responsible before they destroy evidence. Mulder ignores the warning and goes to the morgue. The victim, however, is not Scully.
     Mulder travels to Mrs. Scully's house. Scully suddenly steps into view, leveling a pistol at Mulder's head. Delusional, she claims that Mulder has been lying to her from their very first assignment. But Mrs. Scully convinces her distraught daughter to drop the weapon.
     Mulder realizes that Dr. Stroman's treatment of Patnick was unorthodox. He tracks Stroman and the cable technician to a house on the outskirts of town. Suddenly, gunshots rings out. When Mulder enters the home, he finds X standing over the bodies. X blames the deaths on Mulder. But Mulder counters he never knew who the Plain-Clothed Man was working for.
     Later, Mulder and the now-recovered Scully meet with Skinner. But Mulder does not identify X as the man who killed Stroman and the cable technician.