On the way to the biggest day of his life Sergeant Arthur Diamond and his friend, Cook County coroner Dr Enoch Watkins, are stopped in their tracks by a runaway carriage. While they attend to the casualties and witnesses of the chaos, Diamond fears their delay will derail his hard fought for plans.
At Station House Number Two Lieutenant Billy Doran is making big plans of his own. He hopes to persuade Sergeant Jerry Callaghan into his scheme, but Jerry has a strong sense of self-preservation and his first child on the way.
It may not be as easy as Doran thinks to get his son-in-law on his side.
In their new mystery follow Diamond and Doran as they unravel a web of intrigue and deaths that have their origins in a rare but deadly document.