On summer vacation in their own Brittany, commissioner Georges Dupin finally lets his girl friend Claire Lannoy drag him along to a beach hotel at the quiet Claire Côte de Granit Rose, where the latest murder was in a quarry seven years ago, as the hotel manager eagerly points out. Beach strolling, Dupin meets and befriends real estate tycoon Gilbert Durand, but his a strange feeling about his odd wife Alizée, who shortly after drowns after jumping in the Atlantic ocean, apparently suicide, as both men must watch from land, but the corpse doesn't turn or wash up. Durand suspects a link when another woman mysteriously falls to her death in the quarry, where he met Durand, which the rude owner bluntly refuses access to. Local police chief Desespringalle isn't up to the complicated case, Dupin can't resist butting in.
