Unrequited

U.S. Army Major General Benjamin Block delivers a speech to Vietnam War veterans on the National Mall. Meanwhile, FBI agents, including Mulder, Scully, and Skinner, patrol the crowd in search of a gunman intent on killing Block. Periodically noticing the suspect, they lose sight of him all the time. At one point, Mulder sees the shooter coming straight at him and draws his service weapon, but the shooter disappears into thin air right before his eyes.

Twelve hours earlier, Lieutenant General Peter McDougal was shot in the forehead in a moving limousine. At the scene of the murder, a playing card with a skull and bloody sabers on the shirt was left. The suspect is the limo driver, a young officer Burkholder. The FBI finds out that Burkholder was subscribed to the email mailing lists of the right-wing paramilitary group "Right Hand", which is beginning to be suspected of organizing the murder of McDougal. Mulder and Scully and the takeover team arrest the leader of the Right Hand, Danny Markham, at the organization's headquarters. During the search, the agents find a photo of Markham with Sergeant Nathaniel Teager. Markham says that Tigger fought in Vietnam as part of the special forces "Blood Sabres", which used cards like the one that was left in McDougal's limousine to indicate the murders they committed. The Blood Sabers were on secret missions for the U.S. government, but many of the unit's members, including Tigger, were captured. The command left Tigger in captivity to perish, but the "Right Hand" managed to free him. Meanwhile, Tigger, standing near the Memorial to the victims of the Vietnam War, meets the widow of his colleague Davenport and tells her that her husband is actually alive and is a prisoner. After giving the crying woman her husband's soldier badges, Tigger disappears.

Skinner informs Mulder and Scully that Tigger is officially presumed dead, and his remains are being stored in a Military forensic laboratory. Upon arriving at the lab, Mulder learns that there are only a few of Tigger's teeth, and pulled out with forceps, and the cause of death is recorded as "unproven". Teager's death certificate was signed by General Stefan, and Mulder assumes that Stefan will be the killer's next victim. Mulder manages to warn Stefan of the danger, but Tigger passes unnoticed by security at the Pentagon and kills Stefan in his office. Scully examines Mrs. Davenport in the hospital, and suggests that Tigger has the ability to create a scotoma, thereby disappearing from view. That explains why the security cameras at the Pentagon showed him.

After meeting with Marita Covarrubias, Mulder learns that Stefan, McDougal, and Block were involved in negotiations for the release of prisoners of war. After the conversation, Mulder comes to the conclusion that the generals deliberately concealed the presence of many prisoners of war, and the government is now eliminating these generals with the help of Tigger, knowing that he will not be stopped anyway.

A military band parade and a Block convoy are heading towards the National Mall. Scully spots Tigger in the crowd of onlookers, but he instantly disappears. In the National Mall, Tigger is spotted in the crowd by his former co-worker Leo Denzinger. Tigger gives him a list of the soldiers who are still being held captive, and disappears again. Seeing Tigger very close to the stage from which Block gives the speech, the FBI agents take the general away, but Mulder guesses that Tigger is already waiting for him in the car. After a brief exchange of gunfire, Skinner is slightly shot through, while Tigger is mortally wounded. Before he dies, Tigger repeats his last name, rank, and unit number several times.

After a certain time, Mulder and Skinner meet near the Memorial to the victims of Vietnam. Skinner informs Mulder that the case for both murders has been transferred to the Pentagon's jurisdiction, and the investigation has determined that the killer was not Tigger, but a mentally unstable veteran named Thomas Lynch, whose identity was also confirmed by Danny Markham. Mulder declares this to be a lie and leaves Skinner with the idea that it could have been Skinner himself, who is also a Vietnam War veteran. With heavy thoughts, Skinner remains at the memorial, looking at the wall with the names of the victims, on which there is also the name of Nathaniel Teager.