Exposition (Initial Situation)
A Stranger Comes to Town
Dedé, the protagonist, agrees to meet with a strange interviewer woman who wants to ask her questions about her famous sisters and their lives and deaths. This brings up all kinds of difficult emotions for Dedé, the only remaining Mirabal sister. In the exposition we find out who the main characters are, the fact that they're real historical figures, and we get the idea that their deaths will be the climax of the novel.
Rising Action (Conflict, Complication)
Rise of the Dragon
Dedé remembers her sisters' youth, when they were growing up under the Trujillo regime and the way that the authoritarian government slowly chipped away at their freedom. Things really come to a head when Minerva, her younger sister, refuses to sleep with the president and he takes revenge by throwing their father in jail. This conflict puts an end to the innocent life the girls have enjoyed.
Climax (Crisis, Turning Point)
After many years working in the underground resistance, Dedé's three sisters are ambushed and murdered on a mountain road after visiting two of their husbands in jail. It is Trujillo's final revenge against the girls. There is no turning back from here; death is final and the conflict between Trujillo and the Mirabals has concluded.
The Last Sister
Dedé and her husband collect the bodies and bring them home. Dedé recognizes that her martyrdom is to live without her sisters. Now that the climax is passed and they are gone, she'll just have to muddle through somehow.
The Novel of Fake Endings
After the sisters' deaths the novel wraps up with an epilogue, then wraps up again with a postscript. We find out "where are they now" for all of the remaining characters and learn what has happened in the Dominican Republic in the intervening years.