Terrorists and Nazi-hunters in Vatican City--a serviceable, derivative suspense debut. Father Giovanni Antonelli is a young Jesuit and revolutionary in Uruguay when he and a fellow priest are arrested during a demonstration, thrown in jail, and threatened. The second priest is tortured, but Antonelli is suddenly swept from prison and put aboard a plane to Rome while his friend remains in jail--an odd fate which Antonelli can't explain to Father Ricci, the Jesuit leader who rescued Antonelli at birth. (He was the bastard son of a seduced teenager and a Rumanian Nazi who massacred Jews.) Meanwhile, a N.Y. Jewish lawyer whose relatives were murdered by the Rumanian sees Giovanni's photograph and is certain that he is the son of the Rumanian--so he flies to Rome and begins seeking the madman. There's also a German who is seeking the Rumanian killer for his own purposes: to cut himself in on a diamond cache that the Rumanian ran off with. And. . . Father Ricci himself wants vengeance on the Rumanian--who murdered Ricci's brother. Then, when the German kidnaps Giovanni for a heavy ransom, the Rumanian, now a wealthy businessman in Montevideo, comes out of hiding and flies to Rome to untangle the kidnap scheme. . . . Over-plotted, with a heavy debt to Goldman's Marathon Man, but lively enough action-suspense for especially tolerant, war-crime-oriented readers.