In the ninth Gil Cunningham mystery set in medieval Glasgow, the crime-solving notary investigates the slaying of a woman found dead outside a cathedral.

Tied to St. Mungo's Cross by the cathedral, to be cured of her madness overnight by the saint, a young woman is found in the morning beaten and strangled, still tied to the cross.

Who would flout the saint's protection like this? And who is stealing cathedral property? The crows are gathering about Glasgow, watching the movements of clergy and townspeople.

Gil Cunningham must investigate the dead woman, track down the thieves, and identify the watchers in the shadows, particularly the elusive fourth person who holds the secret of what happened in the night. While his wife Alys deals with tensions within the family, Gil questions cathedral staff and apprentice boys, pilgrims and tradesmen, but he uncovers only more puzzles. And then there is another death. How are the murders connected?