The era of the Napoleonic wars. Great Britain is fighting with French troops. Meanwhile, in the most rebellious of the British colonies - Ireland - the seeds of an anti-English uprising are ripening... A secret organization of English counterintelligence is trying to find and neutralize the legendary French spy nicknamed the Black Tulip, who is at the head of another conspiracy. It is this mission entrusted to Sir Geoffrey Pinchingdale-Snipe. His young wife, Letty, follows his husband to the Emerald Isle. She still does not know that soon she will plunge into a whirlpool of deadly adventures and become for Sir Pinchingdale-Snipe not only a devoted friend, but also a faithful assistant...