A young boy in Oklahoma named Billy Underwood goes missing from a school fair in 1990; as his pregnant mother desperately searches for him, a suspicious-looking teen drops Billy's backpack and walks away. Ten years later, the mother has raised another son named Josh when Billy suddenly reappears, the same age and mute. Billy is taken home, where the dog acts uncharacteristically vicious toward him and Josh also seems a little creeped out by him. Scully finds that Billy's medical stats are identical to ones that were taken shortly before he disappeared, an apparent medical impossibility she's only seen in alien abduction cases.
Doggett finds Ronald Purnell, the teen from 1990 who was questioned and dismissed as a suspect in Billy's disappearance, but Purnell refuses to visit Billy. Doggett looks wistfully at a photo of a young boy in his wallet after this meeting, but nothing more comes of that this episode. Meanwhile, Billy has snuck into Josh's room and jammed a knife into his bed, leaving a bloodstain but no injury on Josh. The blood matches Billy, and a symbol on the knife matches one that Billy had been drawing after his reappearance. A redneck named Cal Jeppy comes to see Purnell's mother and gives Purnell a hard time; Purnell wanders out into the woods and uncovers a child's skull, apparently knowing exactly where to dig to find it.
After further unsettling his family, the Underwoods bring in a shrink, who says a force is drawing Billy to Josh and that Doggett is playing a part in the whole thing as well; the shrink then has a seizure and the symbol appears on her forehead. Purnell shows up at the Underwoods, and is surprised when Billy appears in his passenger seat; after a brief chase, the agents find that Billy is gone. Elsewhere, Josh checks out a pony in a horse cart and is abducted...apparently by Jeppy, who runs a ride-along attraction with a symbol matching the one that's been showing up.
Under interrogation, Purnell says that he knew about Billy's kidnapping but was trying to make it so he wasn't scared. Purnell gives up Jeppy's name and the feds storm his place, rescuing Josh; Jeppy denies having any other child there. Doggett sees Billy again, but he disappears. When Doggett runs over to check it out, he finds the skull that was previously uncovered. The rest of the body is also there and is a complete match for Billy. Doggett is baffled and unwilling to accept a "justice from beyond the grave" explanation, but Scully says that he succeeded no matter what since Josh is still alive.
Episode Body Count
Billy Underwood: found buried near Cal Jeppy's residence.
Cumulative Body Count (166/202 episodes, 1/2 movies)
Humans: 1,744Creatures: 116
Grand Total: 1,923