The Nightmare follows eight people who suffer from sleep paralysis, a condition that is still relatively unknown. People suffering from this can spend their whole life without getting any treatment. When suffering from the phenomenon, it is temporarily impossible to move, to speak or even to react to what is happening around you. You can also experience terrifying hallucinations from which you cannot escape.

Rodney Ascher interviews several people who want to talk about their condition. With a number of  professional actors Ascher then tries to recreate what these people have been through in order to get an idea of ​​what they experience at night. The result is a realistic and most frightening portrait.