Here's the start of my Dan Brown sequel synopsis (I chose Chicago and US Postal Service):
When celebrated Harvard symbologist Robert Langdon is summoned to Wrigley
Field to analyze a mysterious ancient script—imprinted on a gold ring lying next
to the disemboweled corpse of the head docent—he discovers evidence of the
unthinkable: the resurgence of the ancient cult of the Destifori, a secret
branch of the United States Postal Service that has surfaced from the shadows to
carry out its legendary vendetta against its mortal enemy, the Vatican.