The scriptwriters Robert P. Olsson and Tommy Staaff Karlsson spend one night in the lighthouse (called Skage fyr), the same lighthouse used the film, for inspiration for the script. They wrote most of the storyline during that night. The Lighthouse has no electricity and is said to be haunted.
A new ending was shot in August 2009.
The characters names Philip and Håvard is named after H.P. Lovecraft. Håvard is a Norwegian take on the name Howard.