The unnamed narrator reads emails from Bruno Lacombe to Pascal Balmy, which she has been intercepting in secret. Bruno's emails focus on his theories about Neanderthals, whom he affectionately calls 'Thals.' He claims they were prone to depression, addiction, and especially smoking, possibly extracting nicotine from tobacco leaves before fire was discovered for that purpose.

As the narrator translates Bruno's French prose into English, she layers her own imaginative associations onto his descriptions: a 1950s greaser lighting a cigarette, a king-of-the-road biker on a chopper, and the dramatic face of Joan Crawford, whose features she superimposes onto every Neanderthal in her mental natural history museum.

Bruno describes the Neanderthals' large braincases (1,800 cubic centimeters), big faces, fair skin, red hair, and emotional intensity. He attributes to them mathematical ability, dislike of crowds, vulnerability to tooth decay, and overdeveloped jaws he calls a 'sunk cost,' framing the body as a fixed capital investment. He praises their cold-resistant builds compared to modern humans, insisting the standard story of their extinction must be complicated to understand the present and the future.

The narrator reveals her immediate purpose: tomorrow she will meet Pascal Balmy, leader of a group called Le Moulin and the recipient of Bruno's emails, at the Café de la Route in the village of Vantôme at one p.m.