Kansas City, 1934. Devlin Caine, a WWI veteran and former Pinkerton's operative, is hired by a wealthy industrialist to check out a potential business partner. The job is simple and the money good, but for Caine, it's a short step from checking public records to being roughed up in a back alley. Clearly there are things the client neglected to mention, such as Caine's predecessor on the job being found in the Missouri River with a slug in his chest. When the man Caine is investigating turns up murdered as well, Caine finds himself in the middle of a power struggle between his client, a competing industrialist, and a local underworld boss – all after a coded notebook Caine found in the dead man's hotel room. Desperate to unlock the mystery of the notebook (and to protect his client's beautiful young daughter), Caine plays the three men against each other in an effort to buy time. He knows only one of the three rivals can win this battle, and backing the wrong side will cost lives, starting with his own.