Thérèse Raquin
By Èmile Zola

This is not particularly highbrow; it's a little soap opera-ish. Thérèse has a dreary life with her husband and his mother in 19th-century Paris. She starts an affair with her husband's coworker, and together they conspire to kill her husband. Toward the end of the story, the pair have exactly what they wanted—except now they can't bear to be alone together. They feel as if her husband's corpse is with them all the time. It's just devastating, that discovery. I've always found Thérèse Raquin compelling—how these two are ultimately suffocated by their own guilt and conscience.