Passionate social concern distinguishes this otherwise undistinguished novel by the author of Leaving the Land (1984), The Turkey War (1988), and El Yanqui (1986). The latter had began the story of Diego, an American exchange student whose life with his host family in Buenos Aires during the 1960s comprised an education in the harsh realities of Latin American power politics. Unger's sequel returns Diego, now a journalist and newly married, to the Beneventos, who still grieve for their dead and ``disappeared'' sons, victims of the military government that tortured and murdered thousands of innocent citizens during Argentina's ``dirty war'' of 197683. Now, almost a decade later, Argentina has ``decided to put on trial its former government for human rights abuses.'' As Pap† Benevento steels himself to testify, Diego encounters several people who knew the family's sons, and each has a story to tell. Wherein lies the problem: Information is conveyed through conversations, and characters talk to, and at, one another incessantly (for example, enjoyment of a pleasant meal inspires a lead-footed discussion of the Argentine economy). Fitful attempts at drama include Diego's confused relationship with his culture-shocked wife and ominous indications that those scheduled to give testimony against the defendants are indeed in danger. The details of arrest and torture are inevitably compelling, but they're swallowed up in a torrent of generalization. Only near the story's conclusion do narrative and commentary fuse effectively, creating a sense of urgency otherwise lacking: Pap† Benevento's day in court makes for a powerful climax, and the decision of Argentina's ``new democracy'' to pardon the indicted officers in the interests of healing the nation's wounds vibrates with bitter irony. The Beneventos pay the price for their courage and decency, and Diego returns to America ruefully aware that ``we were the lucky ones. We were Americans.'' As an act of witness and accusation, Unger's fourth book is altogether admirable; as a novel, it's a disheartening failure.