The story takes place during the Vietnam War (1964-1975) in Saigon, a wealthy city in the South of Vietnam. Two sisters of of fifteen and fourteen years old are arrested by the South Vietnamese authorities. Afterwards, they're brought to the prison island of Poulo Condor (or Côn Sơn Island) in order to be interogated and tortured. As we follow their lifein prison, we also see through flashbacks the events that these sisters had gone through before their imprisonment such as the Tet Offensive (1968) and even their childhood.
While many Vietnamese novelists like Duong Thu Huong (for her novel Novel Without a Name) or Bao Ninh (for his novel The Sorrow of War) focused on what it's like to be on the battlefield, French novelist Anna Moï adopts a different approach. This means that her novel aims to follow its two leading characters and educate us about the history of the Vietnam War. On the latter point, Riz noir contains a lot of useful informations on how the South Vietnamese handled the war and the repression that came with it. However, by trying to educate us on the Vietnamese past, Anna Moï often forgets to focus on the two leading characters. In fact, why did these two girls get imprisoned in the first place? Is it because of their political activity? All in all, the novel doesn't try to answer to that question.
Finally, Riz noir can be read very quickly. However, the book looks more like a concise book about the Vietnam War rather than a novel that both describe the historical events and the characters.