Scotland Yard's new chief inspector Nicholas Drummond is on the first flight to New York when he learns his colleague, Elaine York, the "minder" of the Crown Jewels for the "Jewel of the Lion" exhibit at the Metropolitan Museum of Art, was found murdered. Then the centerpiece of the exhibit, the infamous Koh-i-Noor Diamond, is stolen from the Queen Mother's crown. FBI Special Agents Lacey Sherlock and Dillon Savich don't hesitate to help Drummond find the cunning international thief known as the Fox. Nicholas Drummond, along with his partner, FBI Special Agent Mike Caine, lay it on the line to retrieve the diamond for Queen and country.