In a snowbound village in the German mountains, a young woman discovers an extraordinary secret. Before she can reveal it, she disappears. All that survives is a picture of a mysterious medieval playing card that has perplexed scholars for centuries.

Nick Ash does research for the FBI in New York. Six months ago his girlfriend Gillian walked out and broke his heart. Now he's the only person who can save her - if it's not too late. Within hours of getting her message, Nick finds himself on the run, delving deep into the past before it catches up with him.

Hunted across Europe, Nick follows Gillian's trail into the heart of a five-hundred-year-old mystery. But across the centuries, powerful forces are closing around him. There are men who have devoted their lives to keeping the secret, and they will stop at nothing to protect it.