The main character is a friar by the name of Brother Athelstan who with a knight named Jack Cranston investigates mysteries. This one is set just before the peasant revolt in 1381 led by Wat Tyler, and the angry feeling of frustration and injustice steeps through the book.
By the end of the book, the story has covered Greek fire, the crusades, John of Gaunt, a supposed miracle, Varangers in Constantinople, and more. The overall story is a mystery of who killed a powerful merchant lord and who is burning to death various folks involved in the trial of that man's wife for his murder.
Like the previous book of Doherty's I read, its a mix of great and poor. Uneven, it handles many concepts and topics well, but is so repetitive about basic clues and information (repeating line for line exact descriptions or statements) that it feels like a US TV show that recaps after every advertising block. Worse still, the final unveiling of the mystery was in bad faith: it relied on several pieces of information not given until the final explanation, and there was no pattern or logical chain the main detective followed to reach his conclusions, he simply didn't know what was going on, then did.
Still, the story was interesting and the characters well crafted and enjoyable. The setting is steeped in Medieval culture and scenery, and it has a very strong sense of time and location. The historical elements are well-researched, and I enjoyed reading about the mystery, even if it wasn't well crafted.