Prologue
 
Nazi-occupied Norway, February 27, 1943

In a staggered line, the nine saboteurs cut across the mountain slope. Instinct, more than the dim light of the moon, guided the young men. They threaded through the stands of pine and traversed down the sharp, uneven terrain, much of it pocked with empty hollows and thick drifts of snow. Dressed in white camouflage suits over their British Army uniforms, the men looked like phantoms haunting the woods. They moved as quietly as ghosts, the silence broken only by the swoosh of their skis and the occasional slap of a pole against an unseen branch. The warm, steady wind that blew through the Vestfjord Valley dampered even these sounds. It was the same wind that would eventually, they hoped, blow their tracks away.

A mile into the trek from their base hut, the woods became too dense and steep for them to continue by any means other than on foot. The young Norwegians unfastened their skis and hoisted them to their shoulders. It was still tough going. Carrying rucksacks filled with thirty-five pounds of survival gear, and armed with submachine guns, grenades, pistols, explosives, and knives, they waded, slid, and clambered their way down through the heavy, wet snow. Under the weight of their equipment they occasionally sank to their waists in the drifts. The darkness, thickening when the low clouds hid the moon, didn’t help matters.

Finally the forest cleared. The men came onto the road that ran across the northern side of Vestfjord Valley toward Lake Møs to the west and the town of Rjukan a few miles to the east. Directly south, an eagle’s swoop over the precipitous Måna River gorge, stood Vemork, their target.

Despite the distance across the gorge and the wind singing in their ears, the commandos could hear the low hum of the hydroelectric plant. The power station and eight-story hydrogen plant in front of it were perched on a ledge overhanging the gorge. From there it was a six-hundred-foot drop to the Måna River, which snaked through the valley below. It was a valley so deep, the sun rarely reached its base.

Had Hitler not invaded Norway, had the Germans not seized control of the plant, Vemork would have been lit up like a beacon. But now, its windows were blacked out to deter nighttime raids by Allied bombers. Three sets of cables stretched across the valley to discourage low-flying air attacks during the day as well.

In dark silhouette, the plant looked an imposing fortress on an icy crag of rock. A single-lane suspension bridge provided the only point of entry for workers and vehicles, and it was closely guarded. Mines were scattered about the surrounding hillsides. Patrols frequently swept the grounds. Searchlights, sirens, machine-gun nests, and a troop barracks were also at the ready.

And now the commandos were going to break into it.

Standing at the edge of the road, they were mesmerized by their first sight of Vemork. They did not need the bright of day to know its legion of defenses. They had studied scores of reconnaissance photographs, read reams of intelligence, memorized blueprints, and practiced setting their explosive charges dozens of times on a dummy model of the target. Each man could navigate every path, corridor, and stairwell of the plant in his mind’s eye.

They were not the first to try to blow up Vemork. Many had already died in the attempt. While war raged across Europe, Russia, North Africa, and in the Pacific, while battalions of tanks, squadrons of bombers, fleets of submarines and destroyers, and millions of soldiers faced off against each other in a global conflict, it was this plant, hidden away deep in the rugged Norwegian wilds, that Allied leaders believed lay on the thin line separating victory and defeat.

For all their intricate knowledge of Vemork, the nine were still not exactly sure how this target could possibly be of such value. They had been told that the plant produced something called heavy water, and that with this mysterious substance the Nazis might be able “to blow up a good part of London.” The saboteurs assumed this was an exaggeration to ensure their full commitment to the job.

And they were committed, no matter the price, which would likely include their own lives. From the start, they had known that the odds of their survival were long. They might get inside the plant and complete their mission, but getting out and away would be another story. If necessary, they would try to fight their way out, but escape was unlikely. Resolved not to be captured alive, each of them carried a cyanide pill encased in rubber, stashed in a lapel or waistband.

There were nerves about the operation, for sure, but a sense of fatalism prevailed. For many months now they had been away from their homes, training, planning, and preparing. Now at least they were about to act. If they died, if they “went west,” as many in their special company already had in other operations, so be it. At least they would have had their chance to fight. In a war such as this one, most expected to die, sooner or later.

Back in England, the mastermind of the operation, Leif Tronstad, was awaiting news of the operation. Before the commandos left for their mission, he had promised them that their feats would be remembered for a hundred years. But none of the men were there for history. If you went to the heart of the question, none of them were there for heavy water, or for London. They had seen their country invaded by the Germans, their friends killed and humiliated, their families starved, their rights curtailed. They were there for Norway, for the freedom of its lands and people from Nazi rule.

Their moment now at hand, the saboteurs refastened their skis and started down the road through the darkness.
 
 
1
 
The Water
 
On February 14, 1940, Jacques Allier, a middle-aged, nattily dressed banker, hurried through the doors of the Hotel Majestic, on Rue la Pérouse. Situated near the Arc de Triomphe, the landmark hotel had welcomed everyone from diplomats attending the Versailles peace talks in 1919 to the influx of artists who made the City of Light famous in the decade that followed. Now, with all of France braced for a German invasion, likely to begin with a thrust through Belgium, and Paris largely evacuated, a shell of its former self, conversation at the hotel was once again all about war. Allier crossed the lobby. He was not there on bank business but rather as an agent of the Deuxième Bureau, the French internal spy agency. Raoul Dautry, the minister of armaments, and physicist Frédéric Joliot-Curie were waiting for him, and their discussion involved the waging of a very different kind of war.

Joliot-Curie, who with his wife, Irène, had won the Nobel Prize for the discovery that stable elements could be made radioactive by artificial or induced methods, explained to Allier that he was now in the middle of constructing a machine to exploit the energy held within atoms. Most likely it would serve to power submarines, but it had the potential for developing an unsurpassed explosive. He needed Allier’s help. It was the same pitch Joliot-Curie had given Dautry months before, one made all the more forceful by the suggestion that the energy held within an ordinary kitchen table, if unlocked, could turn the world into a ball of fire. Allier offered to do whatever he could to help the scientist.

Joliot-Curie explained that he needed a special ingredient for his experiments​ — ​heavy water​ — ​and that there was only one company in the world that produced it to any quantity: Norsk Hydro, in Norway. As an official at the Banque de Paris et des Pays-Bas, which owned a majority stake in the Norwegian concern, Allier was ideally positioned to obtain whatever supplies Norsk Hydro had at its Vemork plant as quickly and discreetly as possible. The French prime minister himself, Édouard Daladier, had already signed off on the mission.