David Daguerre (Jean-Louis Trintignant) shows up at the home of married couple Thomas (Philippe Noiret) and Julia Berthelot (Marlène Jobert), appearing to have been brutally attacked. Daguerre, whom they've never set eyes on before, claims he was beaten up by police who will stop at nothing to get hold of his "secret." Convinced by the stranger's story, the pair help Daguerre cross the border into Spain -- but steadily begin to doubt his sanity and the reality of his persecution.