Mulder and Scully investigate after a virulent tropical disease is introduced into a prison by an infected parcel. The situation is complicated by the escape of two potentially infected inmates.
- Artistic License Military: The opening scene features soldiers from Costa Rica responding to Osbourne's distress signal, even though Costa Rica doesn't have a standing military (though it's also possible they're mercenaries working for Pinck Pharmaceuticals).
- Asshole Victim: The two escaped prisoners who were exposed to the deadly virus by the company. It's difficult to feel sorry for either of them, after they brutally murder an innocent man in front of his wife and children just to steal their RV. One of them later assaults a gas station attendant and possibly infects him with the same virus.
- Awful Truth: At one point, the Smoking Man appears and confirms to Mulder that the government is complicit in covering up the outbreak, if not the initial experiment. He justifies it as necessary to avoid public panic."The truth would have caused panic. Panic would have cost lives. We control the disease by controlling the information."
- Body Horror: Victims of the plague develop rashes and grotesque, exploding boils as the virus gestates within them.
- Cardboard Prison: Two men escape from the prison by hiding in the laundry cart while the laundry is supposed to be getting incinerated due to the quarantine.
- Covered in Gunge: Well, not covered, but Dr. Osbourne and the convict's wife do get a face full of pus.
- It Has Only Just Begun: Said practically verbatim by Skinner in the episode's epilogue.
- Mega-Corp: Pinck Pharmaceuticals.
- The Plague: An unknown virus from South America with a mortality rate near 100 percent.
- Unwitting Test Subject: It's implied that Pinck, or possibly the government, deliberately arranged the outbreak in an effort to practice quarantine procedures at the prison. The prisoners escaping throws a spanner in the works.