Floyd Macklin escapes from custody after being sentenced to 20 years in prison for black marketing activities. He vows to kill the prosecutor and Maj. Caldwell, who were responsible for his capture. Jake sets up a meeting with Macklin to talk to him, but the police arrive and Macklin bolts. Jake finds himself under arrest on suspicion of helping Macklin escape in the first place.
Jake is about to deliver to Maj. Caldwell some microfilm that identifies 12 major gangland leaders at a secret summit meeting. Before he can, though, they're attacked by a gang of toughs and Caldwell is wounded.
Aline Masterson, a New York museum official, hires Jake to recover the Royal Crown of Bosnia, which was stolen from her outside the Hofberg Museum. Jake manages to find the thief who has it and arranges to deliver a payoff to him. However, when he gets to the pre-arranged spot he is attacked and knocked unconscious. When he awakes he finds that both he and Masterson are suspected of being part of the scheme themselves.
A former girlfriend of Jake's, Annalisa, contacts him and asks him to help her husband, who is in jail accused of murdering his business partner over a valuable oil lease. She claims he is innocent of the crime, and Jake's interest is further piqued when a wealthy but shady Turk warns him to stay out of the situation.