The notorious Puritan iconoclast Dick Culmer is killed on London Bridge. Thomas Chaloner's investigation connects the victim to religious radicals who believe the Restoration has betrayed England's godly cause.
Inside Whitehall, Chaloner detects signs of a more ambitious conspiracy involving explosives and an attack on the restored government. He must navigate genuine dissent, fabricated evidence and rival intelligence networks to identify which rebels are prepared to turn anger into mass killing—and who within the court may be helping them.