Instead of just describing the plot, I’m going to use the author’s own words in a recent interview to give you her view.
“Blythe Connor comes from a long history of women who have struggled with motherhood, but she’s determined to break the cycle with her own daughter, Violet. Not long after Violet is born, though, Blythe begins to suspect something isn’t right—she’s different than other children her age and acts in malicious ways. Her husband can’t see what Blythe sees—he thinks her concerns about Violet are all in her head. But when everything Blythe fears is crystalized into one tragic moment, they all must reckon with the repercussions, and the unsettling notion that she might have been right. It’s a story about the anxieties and expectations of motherhood, whether we can ever really know the people we hold closest, and what happens when we don’t listen to women’s truths.”