In The Barbed Crown, the sixth tale of rogue and adventurer Ethan Gage by William Dietrich, our hero returns to Paris and London. Against a background of imperial pomp and the gathering clouds of war, Gage plots revenge on Napoleon Bonaparte for the kidnap of his son.

Paris, the "City of Lights," shines – but alongside its splendor is great squalor. Heroic patriotism rubs against mean ambition, while grand strategy and back–alley conspiracy are never far apart.

While Ethan spies on the French court, his wife, Astiza, works to sabotage Napoleon's coronation using the Crown of Thorns, a legendary relic said to have come from the Crucifixion itself. But when Napoleon is crowned nonetheless, they flee to England.

At Walmer Castle on the English coast, Gage joins a daring campaign by Smith, Fulton, rocket inventor William Congreve and smuggler Tom Johnstone to halt Napoleon's intended invasion of England – a campaign which leads Ethan to take a role in the Battle of Trafalgar itself...