From the introduction: On the first day of every hundredth year magic, The Pack, and The Snarl return to the realm of mortals. “We are The Pack,” says an authority that speaks to every living creature. “If your Heart is ready you can enter The Snarl. If your Will is strong you can reach its end. If you are First, we will reward you with your greatest desire. Come find us.” On the first day of the next year, all of that disappears for another 99 years.