The ritual performed in the movie is the Abramelin Operation, an occult rite attempted by gnostics such as Aleister Crowley. The ritual is meant to obtain "the knowledge and conversation" of the ritualist's guardian angel.
Wrongly considered an error, director Liam Gavin chose not to depict actual parts of the ritual and asked artists to change all symbols out of superstition and respect for the process.
The house in which the majority of the film takes place was made up of two locations: a mansion in Ireland's countryside that was used for the exterior shots and a townhouse in suburban Dublin that was used for all interior shots.
Director Liam Gavin only had 20 days to shoot the entire film.