“This time we have at our disposal two navy patrol boats,” the commissaire said with pride as he pointed with a long stick to the blown-up map on the wall behind him. “One will be blocking the entrance to the bay, and the other will patrol the big sandbank and Île aux Oiseaux, containing some of the most valuable oyster beds. We have three helicopters equipped with infrared vision and night sights and full of heavily armed gendarmes mobiles in case of trouble. We’ve even been allotted a squadron of Republican Guards standing by with tracked armored cars, which are much more mobile on the beaches than wheeled vehicles.”

Bruno had heard from one of the Bordeaux cops he’d worked with before that the commissaire had even persuaded the local prefect to activate an old nineteenth-century statute to recruit gardes-jurés, formally sworn informants among the local oystermen. They might be sworn, Bruno thought to himself, but he had no idea how far they could be trusted. They were still part of a tight-knit local community of seamen, no more than a couple of hundred families who had intermarried for centuries. He’d heard of some families who had worked the oysters of the bay for six or seven generations. They had their own codes and their own rules, and they knew the local waters, tides, and currents better than any French naval patrol boat did.

Bruno knew that all these techniques had been tried before, and the culprits had not been caught. The thieves were probably local people who knew these waters, knew the routes and the back roads, and probably expected the police operation. The end of the year was the most lucrative time of year for the oystermen.

Until this point, Bruno had barely been paying attention. His thoughts kept straying to Isabelle, who was hurtling toward him from Paris on a high-speed train for another of their snatched, occasional reunions. He’d be working each night, so their time together would be limited to lunches and languid, loving afternoons.

Suddenly Bruno sat up, startled by the commissaire’s confident new tone. This time, he was saying, they had a secret weapon. Working with a new French high-tech company, they had developed artificial oysters that contained a transmitter that could be tracked. Each of the transmitters had a different code, so they could see at once which of the many sprawling oyster beds was being targeted. Six drones would be flying over the main beds, tracking the movements of the fake oysters. On shore there were roadblocks to stop each of the big refrigerated trucks that would be waiting to haul up to twenty tons of oysters to the hungry consumers of France.