An old woman who sells flowers is killed outside of Jake's Bar, but Maj. Caldwell believes that Jake was the actual target. Jake, however, doesn't think so, and focuses his attention on one of the mourners at the woman's funeral.
Jake's search for a stolen emerald leads him to a tunnel underneath the Hofburg Palace that is filled with plaster models of various monuments. However, he finds that he's not the only person who's down there looking for the emerald.
In Vienna Jake unexpectedly bumps into Charley Stokes, a man he saw killed in Albania after they had blown up a power station. Charley tells him that he was seriously wounded but saved by Olga Compani, who was the second in command of the Albanian secret police, and that the two are now married. Jake, however, finds the whole incident fishy and suspects that the pair have something planned, and he wants to find out what it is.
Jake finds out that Frank Cort, a professional mercenary, has arrived in Vienna with a beautiful blonde. He suspects that Cort is in town to see Vasamumbo, the former leader of the African nation of Upper Namba for whom Cort commanded a mercenary army and who was deposed in a revolution, and Gen. Gundarson, the commander of UN troops in the country which is the only force strong enough to stop Cort from re-installing Vasamumbo to power.