Midwinter 1460, five years into the bloody quarrel between the noble houses of York and Lancaster that will tear England apart for the next quarter of a century. Caught outside the walls of her priory, Katherine, a young nun, is assaulted by Edmund Riven and his henchmen. She fights back fiercely, severely injuring Riven. Thomas, a holy brother, comes to her aid. When Edmund’s father Sir Giles arrives with his entourage seeking revenge, blood is shed, men and women are murdered, and Katherine and Thomas are forced to leave the safety of their priory and escape into the ravaged, war-torn land.