Liminal RPG Core Rulebook - Rules of Play says:
Liminal is a self-contained tabletop roleplaying game about those on the boundary between the modern day United Kingdom and the Hidden World- the world of secret societies of magicians, a police division investigating Fortean crimes, fae courts, werewolf gangs, and haunted places where the walls between worlds are thin. The players portray Liminals - those who stand between the mortal and magical realms, with ties to each.