“He’d sabotaged rail lines and power stations across France, killed countless enemy soldiers, and even escaped an enemy firing squad. But behind his outward-facing élan, he was racked by secret doubts.”

By Paul Kix

ROBERT DE LA Rochefoucauld, France’s most daring Second World War saboteur and special operative, accepted his most challenging mission in April 1945, in the Gironde estuary off France’s southwest coast.

France had been liberated the previous year, yet isolated pockets of German holdouts remained ensconced in their fortifications. Allied bombers had just “drenched” the towns region, in the words of the New York Times, with a new incendiary weapon called napalm. The German casemates remained intact. The squat, foreboding, cement-fortified anti-aircraft artillery compounds, each armed with 280-millimeter guns, were everywhere along the beaches. Their defenders had no intention of surrendering. One fortress in particular kept La Rochefoucauld’s unit from advancing and finally securing the area.

Then La Rochefoucauld had an idea. The casemate in question sat near the water’s edge—a small inlet flowed behind the compound. The 21-year-old Parisian aristocrat proposed using an inflatable raft to sneak a demolitions team behind the casemate under cover of darkness. The party could then plant plastic explosives on the structure’s outer wall undetected. La Rochefoucauld volunteered to lead the team personally.

The commanding officer was skeptical, but ultimately told the young saboteur to find a rubber boat.

Around 10 p.m. that night La Rochefoucauld and three other men set off. Stowed in the raft were an assortment of rope and explosives along with some submachine guns. There was no moon; a light rain fell — the perfect conditions for a stealth operation.

The team’s paddles dipped into the dark surface of the estuary, driving the boat ahead, lightly, rhythmically. The noise of wood against water was almost inaudible. No one dared speak. It was a mile-and-a-half to their landing spot.

The dark and the silence allowed for some inward reflection. La Rochefoucauld no doubt felt self-assured. Over the past three years, he’d sabotaged rail lines and power stations across France, killed countless enemy soldiers, and even escaped capture and an enemy firing squad. On one mission, he had dressed like a nun to avoid detection only to later place bombs in the enemy’s own bread. Joining the French Resistance and later the Special Operations Executive, he’d literally grown up at war. Now, with final victory within sight, he was embarking on what could very well be his final mission. But behind his outward-facing élan, he was racked by secret doubts. Would his good fortune hold out this time?

As a youngster, La Rochefoucauld had been a poor student, but he was smart enough to know that luck and maybe even God’s grace had brought him to this night as much as his sangfroid. “Perfect bravery and sheer cowardice are two extremes rarely found,” a past Duke of La Rochefoucauld had written in 1665. “The space between them is vast, and embraces all other sorts of courage.” But Robert had come too far to turn around now.

It took two hours before the small group could make out their darkened landing spot on the shore. Slowly, they paddled to the beach and disembarked, taking their guns and supplies with them. The men fell into single file, La Rochefoucauld in the front, a flashlight guiding him. He hoped with each new step to avoid the mines that likely surrounded them. After advancing inch by inch, they saw rising up from the gloom the outline of the casemate. They also saw a problem.

Their target was protected by an outer wall that ringed the casemate. Between that outer wall and the fortress was an eight-foot wide gap that ran between the structure and the barrier. It was concealed by camouflage netting. La Rochefoucauld quickly improvised a strategy. Two of his men would position themselves on the outer side of the wall and keep a lookout. La Rochefoucauld and another man would scale the wall with the explosives and lay prone to avoid detection. Robert would then then crawl out onto the netting, cut a hole through the mesh and drop down into the compound. Once the explosives were lowered to him, he’d plant them along the casemate and return to his comrades. The entire team would then withdraw to their boat.

Robert told his men to be ready. If a guard spotted him on the netting, they would need to open fire, and retreat, leaving him behind if necessary.

The four men approached their objectives with weapons at the ready. A drizzle still fell, which would make the stone wall slippery, but the sound of the rainfall would drown out any noise the team made. The grass was slick with rain water. The team reached the edge of the enemy position and La Rochefoucauld scaled the wall with little noise or difficulty. He knelt on the precipice and peered down. A lone sentry was marching back and forth through the courtyard. The German wore a hooded rain jacket and seemed entirely oblivious to the danger above him. Luck, even on this inclement night, shone once more on La Rochefoucauld.

He put one foot and then one hand on the camouflaged netting. After testing its strength, the young saboteur scrambled out onto the ropes and lay steady, suspended barely a foot above the top of the patrolling enemy’s head. The sentry kept his head down sheltering his face from the weather.

La Rochefoucauld slowly took out his knife and began cutting the links of netting. Each gave way with little to no noise. He redistributed his weight as he cut a wider and wider hole, making sure it opened over the path the guard was walking. The unsuspecting guard still didn’t glance up. After several moments, La Rochefoucauld had sliced a gap large enough to dive through. He looked around, and using hand signals told his team that the next time the guard passed, he’d jump. The enemy infantryman, with his rifle still slung over his shoulder, passed beneath the saboteur one last time.

Robert made his move. He lunged at the German, knocking him off his feet, the rifle clattering to the ground. Adrenaline and his training took over as La Rochefoucauld pulled the Nazi close and sunk a dagger into the man’s throat. The struggle ended almost as soon as it began. La Rochefoucauld dragged the body and leaned it slumping against the wall.

Once the explosives had been passed down to him, La Rochefoucauld moved quickly to place the packages along the casemate’s exterior. He set the timers for seven minutes and had his comrades pull him up to safety.

It was a slow scramble for the men, trying to distance themselves from the casemate, while watching for mines.

The group was about 500 yards from the enemy installation when the explosives went up. The team exchanged satisfied glances, but it was no time to celebrate; soon the countryside would be crawling with Germans. They made for the boat and paddled for safety. It took some time for them to reach the Allied positions. Once safe, the men were suddenly overcome with giddy elation. Their once skeptical commander approached to ask for a report. Upon learning of the mission’s success, his earlier doubts turned to an exhilaration that matched the team’s. He promised La Rochefoucauld and his men that he would nominate them for the Croix de Guerre. La Rochefoucauld blushed, honored, and felt suddenly stunned, too, as he watched a new and wonderful day brightening the skies. He had survived his most dangerous night without so much as a scratch.

Yet as he tried to grab some sleep, a question worked in his mind: Had he actually succeeded? The blast of the explosives had echoed through the night, as loud as any of his other jobs, but the casemate was designed to sustain almost any blow. If the structure survived aerial bombardments, would not be able it withstand plastic explosives? He’d soon have his answer. The following morning, the French column was to advance across ground covered by the casemate’s guns.

The following day, Allied bombers struck the area once more, while artillery lay down fire to cover the ground assault. By 4 p.m., La Rochefoucauld and his regiment moved out under the cover of French tanks. As they drew ever closer to the dreaded casemate, Roberts could finally see the structure in broad daylight. It was disfigured. Gaping holes were torn in to the concrete. No enemy guns fired on them. La Rochefoucauld’s captain fell back in line until he found his commando. “Bravo,” he whispered.

Paul Kix is the author of The Saboteur: The Aristocrat Who Became France’s Most Daring Anti-Nazi Commando. He is a senior editor at ESPN Magazine and has written for numerous publications from the Boston Globe and the Wall Street Journal to The New Yorker. See the trailer for his latest book below.