Plot please?

[Jami]

Years ago I read a book involving a white, northern woman who has an affair with a black plantation owner. The ending was such a disappointment - her southern relatives find out and attack the plantation, he gets shot, she picks up the gun and kneels by his side - that even years later I want to write the author hate mail.

I THINK this one MIGHT be that book, but I can't find a plot description ANYWHERE. Please, does anyone know the plot of this one?