The teacher confronts him for missing the test, but Max grabs the paper and immediately fills it in with all correct answers. The teacher suspects cheating.
The bell rings and the students file out. Mulder and Scully are waiting to interview Chastity, but Max counsels the girl to say nothing since they have no warrant. Mulder observes that Max is the sheriff's son.
Speaking of the sheriff, the local law enforcement office calls with bad news -- the flashlight has disappeared from the evidence locker.
Mulder and Scully review the surveillance tape with the discomfited Sheriff Hardin, who now wants their help.
Fast cars and other high-tech toys
Since there is no longer any hard evidence against him, Tony is sent home. He sulks in his bedroom while his mother questions him about his new friends, who seem like a bad influence.
When Tony look out the window, he sees Max there, beckoning to him. The two go for a fast drive and crash into a tree -- but suddenly, both are standing outside the car, unhurt. Tony is befuddled.
"I'm gonna make you one of us," Max snorts. "But I call the shots. Always remember that."
Meanwhile, Mulder and Scully have brought the surveillance tape to Chuck, a technician interested in the paranormal.
Using software that he's "beta-testing for JPL," Chuck adds color to a mysterious shadow that flits through the hallway on the tape. The local high-school colors appear.
Back at school, Max shows up in the cafeteria (wearing his high-school jacket as usual) and stands there -- his body blurring strangely -- while the teacher is horribly killed by a fast-moving table and chair.
Murderous hormones?
Afterwards, the agents come to the cafeteria to investigate. Mulder notes that Max's grades have improved in recent months, even as he has become a disciplinary problem.
Scully points out that adolescence brings chemical changes. Mulder wonders if it can also bring on paranormal powers.
A deputy enters to tell them Max has collapsed in a parking lot and the sheriff is rushing to meet his son at the hospital.
Meanwhile, Tony follows an unsuspecting Chastity by car and then foot, into a woodland cave.
Once inside the cave, he sees a vertical shaft of light emanating from a hole in the rocks above. When he enters the shaft, he finds that he can swing his arms at superhuman speed.
Live fast, die young
In the hospital, an angry Max turns aside questions from Scully and Mulder. The sheriff defends his son but with an increasingly worried tone. When no one is looking, Chastity shows up with a wheelchair.
Looking at X-rays, Scully is astonished that the young Max has arthritis, stress fractures and general bodily deterioration. "Whatever Max is doing, it's killing him," she intones.
Having weighed all this evidence, Mulder explains that Max's body is falling apart because he's moving around faster than the eye can see, and that this is how he commits murders.
Later, back in the woods, Chastity tells Max he should stop hurting people and get help.
He's not interested, but after he walks off, Tony stumbles by. He's been in the cave, and it's a "rush," moving so fast. Anyway, with Max in the hospital, they can go to the cops. But Chastity says sadly, "He's out."
A fist can hurt as hard as words
At the Hardin house, the worried sheriff is examining his son's bedroom and finds the incriminating flashlight.
Max suddenly appears before him. The boy confesses to killing the deputy and the teacher because their bullying authoritarian personas reminded him of Hardin, whom he loathes.
Wounded not only by these words but by ultrafast blows from Max, the sheriff crumples to the ground. But suddenly, with equally amplified speed, Tony's there, holding a gun to Max's head.
Soon, the sheriff is being wheeled into the hospital on a gurney. Mulder, noting the flashlight is Max's preferred weapon, hypothesizes that someone intervened to stop the latest assault.
Scully says that this was probably Tony, but where can they find him?
Signs of slowing
Night. Tony and Chastity are in a car, racing to get to the cave before Max does. She notes that both boys have slowed down after the recent fight and need a fresh infusion of what the cave has to offer.
But when they get to the cave, Max is already there. He pummels Chastity into seeming unconsciousness, then turns his attention to Tony, who has a gun. Max rapidly retrieves the weapon and sets it on the cave floor, perhaps for later use.
He's about to hurt Tony -- hurt him bad -- when Chastity, having soaked in some of that speed-giving light shaft, whirls behind Max, gun in hand and pumps a bullet straight through his torso.
As Max screams in what seems like slow motion, the ultrafast Chastity zooms around him to tell the fatigued Tony she can’t go back to a slow-paced human life. She then turns to deliberately …
… face the very same bullet that she has just pumped through Max.
Mulder and Scully enter the cave to find Tony grieving over the newly dead Chastity. Max is dead too.
More answers than questions
Later, Mulder tells Scully a team of geologists has now investigated the cave, found nothing unusual, and sealed the place off as a precaution.
When Scully asks what he expected them to find, Mulder gives an eclectic response:
"A vortex like the one in Oregon. Gravitational aberrations. Unique chemical compositions. Relics that would indicate that the cave was a sacred site. Something. Anything. I don't know."
Scully observes that she and Mulder, though they'd been in the cave, had not gotten enhanced speed. Mulder replies that maybe he and Scully are "too old" to be affected by the phenomenon.
Fortunately, Tony is going to recover, they agree. As his mother sits at his bedside, the kid glances meaningfully at a clock on the wall.