It is Sunday morning on the 4th August 1577, in Bongay, a small town in North Suffolk. During a violent thunderstorm, the church is struck by lightning and two parishioners are killed while another is severely injured. Soon afterward, a pamphlet is published claiming that the deaths and injuries were caused by a giant ghostly black dog, which broke down the church door and ran up and down the aisle, attacking all in its path.

The Bishop of Norwich sends Captain Richard Brightwell to investigate the mystery, accompanied by his servant Humfry Trip, his secretary John Kettle and Augustyn, his seven-foot tall mute bodyguard. They soon come to realise that nobody in town is who they appear to be, and while navigating a medieval football match and early street theatre, they become embroiled in mayhem, mystery…and murder.