Monsieur Daron, an eighty-six-year-old-man, comes to live at the new spa in Rondelis. He believes himself to be in excellent health, as a result of "careful living." He has always had "an obsessive fear of death," and he avoids all pleasure because it may be dangerous.

In order to measure and monitor his own condition, M. Daron arranges for the doctor in charge of the springs to visit him once a week with information on the health of everyone else in the surrounding area who is over the age of eighty. When he hears that someone has died, he quickly identifies a cause that might have been avoided; the man who died of pleurisy should not have gone out in the cold, and the one who died of dysentery must have eaten the wrong food.

Eventually, though, one old man dies for no apparent reason. The doctor can report no lesion, no disease: "He died because he died, that's all." M. Daron is horrified and asks the man's age. Eighty-nine. He laughs in relief, saying, "whatever it was, it wasn't old age . . . ."