The fourth case for Capitaine Roger Blanc! Capitaine Roger Blanc and his colleague Marius Tonon are to accompany a mysterious government diving mission on the Côte Bleue. A relaxing job on turquoise blue sea, in front of the pine-clad cliffs of the Mediterranean coast - until an unknown diver floats in the water, a harpoon stuck in his right eye. Everyone believes it was a terrible accident, only Blanc finds this death strange ... He investigates and finds out that Luc Mignaux, the dead man, belonged to the so-called wreck divers, specialists who plunder centuries-old sunken ships in order to sell the loot to rich collectors. It's work that is as dangerous as it is illegal, and disreputable among many locals. Fisherwoman and eco-activist Christin Antunes, in particular, protests vehemently against it. Is that enough of a motive? When it comes to a w.