The story of the making and subsequent success of The Day of the Beast, the Spanish cult film directed by Álex de la Iglesia and released in 1995.

The story revolves around a Basque Roman Catholic priest dedicated to committing as many sins as possible, a death metal salesman from Carabanchel, and the Italian host of a TV show on the occult. These go on a literal "trip" through Christmas-time Madrid to hunt for and prevent the reincarnation of the Antichrist.

Waging war against all things glamorous and beautiful, crippled terrorists Acción Mutante plot a series of attacks on society's elite, and attempt the kidnapping of a wealthy socialite at her elaborate wedding reception.