 When they stop at a gas station, they return to their car to find a razor blade — the Father's calling card — attached to the rear view mirror.Director Marcus Adams recalled producers Alistair MacLean-Clark and Basil Stephens approaching him to direct the film in 2001, which at that time was "essentially a vampire movie," which had been in development for around five years.Adams spent one year rewriting elements of the script with screenwriter Stephen Volk; this included altering the ending as well as subduing the overt vampire plot of the film, resulting in what Adams envisioned as "faint" vampire film, where vampires functioned more as a metaphor than as literal beings.