Young fifties, Jacinthe discovers running. "She's changing," notes Bernard, her partner, in a notebook he fills in for fun because life seems dull to him since he sold his bookstore. To escape boredom, he adopts a cat, which keeps him warm when he writes. The more he writes down his observations, the more he fears losing Jacinthe, who is changing. Helped by the tobacconist, his ally, Bernard prepares his revolt. While one revives, the other sinks. Sweat is a desire for evaporation combines suspense and melancholy in a story full of delicacy.