In October 1975, as every autumn before the migration of immense flocks of wood-pigeons, the Basque region of France attacks groups of privileged hunters.
But Charles Williamsen, an American ornithologist, has come on a different observation mission. His stay takes on a strange and disturbing turn when he is mistaken with a disappeared Basque terrorist and he inadvertently uncovers a plot to assassinate one of the hunters, Rafael Fernandez, a close relation to General Franco.
The situation becomes particularly difficult because the daughter of Fernandez, Miranda, is very much attracted to him.
As the fatal moment nears, Charles finds himself swept in an implacable twist of fate.