From the introduction:
At the ruins of Carterhaugh in the Scottish Borderlands near England, there is a crossroads where the many Worlds meet. Here, at Samhain, Fae and Mortals congregate for their annual Court, hosted by the Fae. At this time, the veils between the Worlds recede, and beings from the Mortal Realms, Faery and other Worlds can come together or cross over from one world to the next. In the limitless, infinite world of the Fae, beings are not limited by space or time. Those who live at radically different times may find each other in company in the same moment.