The kingdom of Fortriu has enjoyed five years of peace since Bridei came to the throne. But now Bridei is preparing for the long-awaited war that he hopes will see the Gaelic invaders driven from the west forever, and he must forge alliances where he can. The princess Ana, a hostage of Fortriu since childhood, is sent north to make a strategic marriage with a chieftain she has never met - and with it gain an ally on whom Bridei's victory relies. Her escort is led by a man she despises: the enigmatic Faolan, Bridei's assassin and spy. The expedition is ill-fated, and when Ana arrives at the chieftain Alpin's stronghold in the mysterious Briar Wood, she is uneasy. This is a place full of secrets. When Ana discovers a prisoner kept within the bleakest of confinement, she is met with a conspiracy of silence. Faolan, torn between duty and an impossible love for the woman he has pledged to see safely wed, walks a delicate path between loyalty and betrayal. Unable to wait for word from Ana, Bridei's forces march into battle. But it is revealed to those left behind that their king heads not only towards defeat, but certain death. There is only one messenger who can reach him in time, but to enlist his services will set brother against brother, and endanger what has become dearest to Ana's heart . . .