Pathologist Dr. Warren Chapin conducts autopsies on executed prisoners, developing a theory that a creature inside each person is responsible for fear. He believes this creature is suppressed by the ability to scream when fear strikes. When he meets the owners of a second-run movie theater, Martha, who is deaf and mute, he sees an opportunity to test his theory.

The Tingler
A pathologist's fascination with a parasite that thrives on its host's fear leads to a descent into darkness and terror.