Carlotto's novel is about as bleak as it can get. I'll try not to spoil the first few pages for you, but let's just say that a jewelry robbery goes very horribly wrong and ends in a terrible crime, which leads one of the robbers to end up in jail for this crime, while his accomplice gets away.
Flash forward fifteen years and a man who's life was ruined by this fiasco receives a letter from a lawyer requesting that he help the incarcerated robber be pardoned on compassionate grounds. Although at first the man refuses, gradually it occurs to him that the imprisoned man might be manipulated into leading him to the accomplice, who has never been caught.
I think the book is a great introduction to noir, because it runs counter to many of our more usual assumptions about what makes a good tale. Neither criminal or victim are exactly what you would call role models, but both have a lot of energy and the stakes are very high. One question that the book raises is whether there can be atonement for horrible crimes. I remember being a bit dissatisfied with Ian McEwan's take on this in his own book, which even takes atonement as its title. Basically, he says no. I think this book provides a slightly different answer. I think what Carlotto would say is that there is no easy atonement. You'll have to read the book to find out why I think the qualifier is important.