1908. When a brilliant American battleship gun designer kills himself, his grief-stricken daughter is deeply suspicious. She turns to the legendary Van Dorn Detective Agency where chief investigator Isaac Bell finds clues that indicate murder.
Uncovering more suspicious deaths, Bell realises that someone an elusive spy is orchestrating the destruction of America's brightest technological minds. And the murders all connect to a top-secret project known as Hull 44.
As Bell gets closer to the truth and the spy himself he is pitted against German, Japanese, and British agents. More than the future of his country is at stake it's the fate of the world.