It's July 1478, and business is good for Bristol's bakers during the lead up to Lammastide - "Loaf-mass", the ancient harvest festival. But the shady Jasper Fairbrother's baking days are over when he's found face down with a knife in his back. Suspicion immediately falls on the mysterious Breton who'd arrived that day. But when it emerges that the Breton is also a suspected Lancastrian spy, Roger the Chapman begins to wonder if suspicion of murder is merely a convenient pretext for the authorities to hunt the man down.