When a school student becomes the prime suspect in the bizarre murder of a police officer, Mulder and Scully are sent to investigate. They discover that the boy and a couple of friends have been playing with the ability to accelerate their movements to a frequency the human eye can’t perceive.
Mulder and Scully later examine the deputy's body: the blow that killed him was so ferocious that his glasses were pushed through the back of his skull. They question the suspect, teenager Anthony Reed, whose fingerprints were found on the flashlight, but he denies any part in the murder. Mulder and Scully agree that Tony is innocent, although Mulder's theory of spirit involvement is not shared by Scully, who prefers a more down-to-earth course of investigation, suggesting they question Tony's friends. Mulder and Scully visit Tony's school and speak with the two teenagers who were with Tony in the woods, sheriff's son Max Harden and his girlfriend Chastity Raines. Chastity seems concerned about Tony when Mulder and Scully tell her he may go to jail. However, Tony is later released when the murder weapon disappears.
Mulder and Scully review video footage of the evidence room that shows the flashlight simply disappear. A blur on the video footage attracts Mulder's attention and later analysis by an expert reveals the blurred object is solid and matches the local high school colors. Later, a teacher whom Max despises confronts him with charges of cheating in the lunch room. Suddenly, witnesses by many students, the teacher is attacked and violently killed by an unseen force, which pins him to the wall with a table and then throws a chair at his head.
Mulder believes Max's changing teenage hormones are giving him paranormal abilities that allow him to attack people without touching them. Tony follows Chastity into a cave in the woods and is suddenly endowed with the same paranormal abilities. Meanwhile, Max collapses and is brought to the hospital, where it is found he is suffering from exhaustion, withdrawal, a concussion, and severe ligament damage. In short, he has pushed himself far beyond what his body is capable of handling. Mulder figures out from the green globs on Max's shoes that he has superhuman speed and is quickly burning out.
Chastity sneaks Max out of the hospital and they return to the cave, where they are met by Tony. The sheriff finds the flashlight in Max's room and confronts his son about the murders. Max confesses and then attempts to kill his father, but Tony intervenes, taking the sheriff's gun. Max is about to shoot Tony when Chastity takes the gun and shoots Max, using her abilities to step in front of the bullet as it passes through him and kill herself as well. After finding nothing to explain how the three teens got their powers, the city decides to fill the cave with concrete, sealing it forever.
- Among the posters on Max's bedroom walls are ones for The Doors, Staind and Busta Rhymes.
- Max tells Scully she must have been a "Betty" back in the day, which is slang for an attractive young woman.
- If Max is moving faster than the eye can see, then so should whatever he is holding, therefore, the table, chair, and other objects he interacts with should not be visible. Presumably, he just threw the chair and table.
- Chastity drives a 1970 Camaro.
- It is unclear what causes the teenagers to become super fast. Although the visual effect when they receive their powers is similar to encounters with alien force fields (TXF: Requiem), it is never established that it is alien technology that caused this.
- The 2012 film Chronicle has been noted to have the same basic plot as this episode, although the three teens in that film are gifted with telekinetic powers rather than super speed.
- The dates on the academic discipline and progress forms for Max are not in accord with the chronological timeline of the series, especially after the previous episode "Millennium". Supposedly, the changes in his behaviour and grades started a few months before, but the reports are from a few years previous.
- When the bullet is seen passing through Max and about to hit Chastity it is perfectly formed, just like it would be when still attached to the casing. In reality, bullets deform significantly when they enter an object such as a human body - typically looking more like a mushroom than a bullet.
- Late in the episode, as Mulder and Scully walk down a hallway, their marks are clearly seen on the floor.
- Scott Cooper, who plays Max Harden, was 29 when this episode was filmed and it showed. Max's looking older than his actual age could be explained by saying that the substance in the cave also accelerated his ageing process slightly, though this doesn't seem to apply to Chastity.
- "You think I'm like Carrie or something? I used some kind of mental powers?" This is an allusion to Carrie by Stephen King, a book and movie about a high school girl with telekinetic powers who rained vengeance upon those who tormented her.
- Max Harden: Yeah, too much teen spirit. Mulder: You think? Smells like murder to me. This is a reference to the song "Smells Like Teen Spirit," by Nirvana.
- Rodney Scott as Anthony Reed
- Scott Cooper as Max Harden
- Nicki Aycox as Chastity Raines
- Ann Dowd as Mrs. Reed
- Tom Bower as Sheriff Harden