Mulder and Scully travel to a strange town where a secret religious cult seems to have unleashed the devil upon the unsuspecting students of a nearby high school.
The Parent-Teachers Committee discuss about the usual things, the upcoming play etc. Before the committee leave they suddenly all light a candle and close the door while chanting to the "Lord of Darkness" and saying "Die Hand Die Verletzt (His is the hand that wounds)".

Meanwhile, in a forest, four teenagers decide to play a bit of a practical joke and attempt the "summon up the devil". As one of the teenagers finishes reading, dozens of rats start swarming around their feet. One of the boys attempts to make a quick getaway but is stopped by a sudden flame and is strangled by an unknown entity. Later he is found with his eyes and his heart cut out.

Mulder and Scully investigate and suspect that the teenagers were trying to summon up the devil but it all went horribly wrong. Scully is skeptical until toads suddenly start raining down on top of them which does leave Scully in a bit of confusion. Meanwhile at the local high school, a Mrs. Paddock is a substitute teacher for a Science class. As the agents interview the three remaining students involved with the ritual, the committee meet again and say that something has been unleashed and that "it" was responsible for the death of the boy. But when Mulder notices that the water is draining down the wrong way he believes that something has been unleashed here as well. As this is going on, Mrs. Paddock opens her desk drawer in secret to reveal the heart and eyes which were removed from the boy.

As one of the students, Shannon (a daughter of one of the PTC members) attempts to dissect a baby piglet, she suddenly sees it screaming and moving and runs off and tells Mulder and Scully the story of how she was taken by a religious cult and made pregnant, the babies being buried. Feeling a bit better, she returns to class on her own and attempts it again but meanwhile Mrs. Paddock possesses Shannon and makes her slit both wrists. Mulder again believes that Black Magic was responsible.

Mulder goes over to talk to Shannon's dad and he tells him that did he "really expect the devil to behave" after a door shuts on him by a mysterious force. He also confesses that he was part of a group that has been worshipping dark forces and that he would confess all to Mulder. Just before he does, Scully rings Mulder telling him that she is in danger at the school but it turns out to be Mrs. Paddock after concentrating on Scully's voice and holding her pen.

Mulder handcuffs Shannon's father in the basement and rushes over to the school. The agents return to the basement to find his remains having been devoured by a snake which was in fact controlled by Mrs. Paddock. The agents return to the school and find a jar containing human eyes. Suddenly, they are jumped on by the PTC group who prepare to sacrifice them to please the devil around them if it's not "already too late".

Just as the agents are about to be killed by a shotgun, Mrs. Paddock controls one of the members who shoots the others and then turns on himself as the teacher says "It is already too late". Mulder and Scully return to find a note on the blackboard reading "Goodbye. It's been nice working with you." as the agents look at each other. We all know what they were thinking.....