What an idyll: the body of wealthy businessman Patric Provost is pulled out of the sea off the beautiful island of Belle-Île. He was strangled to death. Suspects are a dime a dozen, so to speak, as Provost had many enemies: the reclusive and ruthless landowner had numerous animosities and conflicts. Above all, however, there was a simmering atmosphere in his immediate surroundings. There were: Ex-wife Agnès, who now lives with a fisherman, Provost's neighbor and lover Margot, and her opaque husband Byn. Margot and Byn are economically dependent on Provost with their whisky distillery. In his 10th case, Inspector Dupin, who has been transferred from Paris to the Breton coastal town of Concarneau, investigates a complicated web of jealousy and fatal dependencies. And yet, in the midst of this dreamlike, picturesque landscape, the ex-city policeman suspects that there is much more to this murder!