Winter 1379 and trouble is besetting England as French privateers attack the southern coast on a path to London itself. In response, an English flotilla of warships, with God's Bright Light in its number, has dropped anchor in the Thames. When the sun rises on their first morning, however, the first mate and two of the crew of God's Bright Light have disappeared without trace.

Sir John Cranston, the Coroner of the City, and Brother Athelstan, his clerk, are summoned to resolve the mysteries on board the ill-omened warship. In particular, they must search out the truth behind the death of Sir Henry Ospring, who visited the ship's captain prior to his death and was viciously stabbed to death in nearby tavern chamber.

As Cranston and Brother Athelstan investigate, they find themselves in the thick of a bloody battle on the Thames as scandal, treason and murder rule the day.

The fifth book in Paul Doherty's acclaimed Sorrowful Mysteries of Brother Athelstan series.