After living in Australia for the past decade, Fitz and Judith return to Manchester in 2004 for their daughter Katie's wedding. Drinking too much at the reception, Fitz stumbles through a rambling toast, which only embarrasses the bride. Instead of spending time with his grandson, son of his married son Mark, Fitz opts to join in the investigation of a serial killer who has an apparent dislike of Americans in the wake of the U.S. Invasion of Iraq.

A murder in Paris’ Louvre Museum and cryptic clues in some of Leonardo da Vinci’s most famous paintings lead to the discovery of a religious mystery. For 2,000 years a secret society closely guards information that — should it come to light — could rock the very foundations of Christianity.

The wise-cracking Fitz is a brilliant but flawed criminal psychologist with a remarkable insight into the criminal mind.