Cosmétique de l'ennemi begins in a flight departure lounge where a delay is announced, and Jérôme Angust settles down to read a book, but is pestered by a man - Textor Texel - who refuses to stop talking to him even though Angust has made it quite clear that he's annoying him.
Cosmétique de l'ennemi also has similarities to Les catilinaires, where Berdardin tortures Emile and Juliette by holding them prisoner every day when he visits them, only Texel's method is the opposite: Bernardin conveys his existential torment by silence, whereas Texel conveys his to Angust by logorrhea. Angust even uses the same words of Texel as Emil does of Bernardin: 'emmerdeur' ('ball breaker') and 'tortionnaire' ('torturer').
But Texel is much more than a ball breaker, and even more than a torturer: twenty years earlier, he held Angust's wife overnight in a mausoleum in Montparnasse Cemetery and raped her, and stabbed her to death ten years later, exactly ten years before the book is set. He demands that Angust kill him, but the horrified Angust screams for the police to arrest Texel. When the police arrive, they think Angust has had too much to drink during the flight delay, and ignore Texel.
That's just where things begin to get really weird. Texel tells Angust that the police ignored him because he doesn't exist as such: in fact, he's no more than a very different part of Angust himself. He proceeds to tell Angust all he knows about him, which is a great deal: so is Texel trying to send Angust mad, or is he already mad?
Many things in this book will remind the reader of Nothomb's familiar concerns - rape, confinement (the departure lounge, the mausoleum, and above all the prison of one's own mind), psychological torture and freedom, ugliness and beauty, murder, eating disorders, suicide, the hell of other people, orphanhood, the influence of the theater, intertextual references, the monster within and without, etc - but I've not read a book of hers that is as gripping or as terrifying as this.
Whether the reader sees it as a straightforward battle of madness versus sanity, Kierkegaardian asthetics versus ethics, Freudian id versus the superego, Jansenism versus free will, or anything else, this is a very powerful psychological novel.
And it's even been translated in English - as The Enemy's Cosmetic.