Joseph and Celice, a married couple in their fifties, both zoologists, return one day to the coastal dunes where, thirty years before, they had first made love. There they are attacked and beaten to death by a robber. From this starting point, the novel traces three trajectories: their married life, from their meeting as graduate students working at this beach; the course of their last day, traced backwards, or undone, until they are back in bed, asleep, that morning; and the first week of their death until they are found and taken away by the police. The changes that take place as their bodies decay are meticulously described. At the end of the novel, nine days after their death, the grass has recovered and there is no sign they were ever there.