Bobbie Druke (Drew-key), a suburban Minneapolis police detective, and her husband Andy Richards, retired FBI agent, are retained by a Mafia chieftain to track down a mutual enemy, an assassin named Lewis Rose, who has fled to Argentina.
In Buenos Aires, Bobbie and Andy find corruption in the Argentine government's ruling party. The Peronistas have ties to the Argentine Mafia, the C.I.A., and the U.S. State Department and Lewis Rose has become immersed in it all, having taken the sobriquet "Charon", the mythological boatman who ferries souls across the river Styx to Hades. Charon the Ferryman becomes the Peronistas' assassin, as well as the bodyguard and lover of the President's daughter, Zulemita Menendez.
The moderate Alianza party persuades Bobbie and Andy to help stop Charon, but the Ferryman stays a step ahead of them. The chase is on as the Richards follow Lewis and Zulemita Menendez back to the U.S., where Zulemita will attend college at Bryn Mawr, a sister school to Swarthmore College, where Bobbie's daughter is a sophomore. As paths cross again, more people die before Lewis is caught and Bobbie and Andy discover that the Mafia connection in Argentina is more than they could ever have suspected.