Louise initially proves to be indispensible, going out of her way to be a super nanny, not caring about the hours she works, being a super cook, being a true carer.
And then. Cracks begin to appear in the apparent armour of Louise, who performs several odd acts, arousing the suspicions of the husband, but there's nothing concrete.
Somehow, Slimani lets the reader get inside the mind of an insane murderer, makes her seem not quite so insane in her attempt in get wholly inside the world of her employers, makes the reader participate in her pain to some extent, see the way she has been abused, the way she is trying to escape from her inescapable condition, to some extent understand the true nature of the situation. Whatever that is, as we'll of course never know.
So, a very successfully achieved novel, a gripping one, but was this honestly the best French-written novel of 2015? Obviously the women protesting outside the Drouet restaurant had a point about the scarcity of Goncourt-winning women writers, but didn't the fact that the writer is a highly intelligent, highly attractive mixed-race woman play any part in the choice? Of course not, what a stupid thought!