I had never heard of this or ever seen a movie made about this but the story is certainly interesting. This is an amazing story. It seems that days after Hitler’s suicide a group of American soldiers, French prisoners, and, yes, even German soldiers defended an Austrian castle against an SS division—the only time Germans and Allies fought together in World War II. Andrew Roberts on a story so wild that it has to be made into a movie someday.

The most extraordinary things about Stephen Harding’s The Last Battle, a truly incredible tale of World War II, are that it hasn’t been told before in English, and that it hasn’t already been made into a blockbuster Hollywood movie. Here are the basic facts: on 5 May 1945—five days after Hitler’s suicide—three Sherman tanks from the 23rd Tank Battalion of the U.S. 12th Armored Division under the command of Capt. John C. ‘Jack’ Lee Jr., liberated an Austrian castle called Schloss Itter in the Tyrol, a special prison that housed various French VIPs, including the ex-prime ministers Paul Reynaud and Eduard Daladier and former commanders-in-chief Generals Maxime Weygand and Paul Gamelin, amongst several others. Yet when the units of the veteran 17th Waffen-SS Panzer Grenadier Division arrived to recapture the castle and execute the prisoners, Lee’s beleaguered and outnumbered men were joined by anti-Nazi German soldiers of the Wehrmacht, as well as some of the extremely feisty wives and girlfriends of the (needless-to-say hitherto bickering) French VIPs, and together they fought off some of the best crack troops of the Third Reich. Steven Spielberg, how did you miss this story?

The battle for the fairytale, 13th century Castle Itter was the only time in WWII that American and German troops joined forces in combat, and it was also the only time in American history that U.S. troops defended a medieval castle against sustained attack by enemy forces. To make it even more film worthy, two of the women imprisoned at Schloss Itter—Augusta Bruchlen, who was the mistress of the labour leader Leon Jouhaux, and Madame Weygand, the wife General Maxime Weygand—were there because they chose to stand by their men. They, along with Paul Reynaud’s mistress Christiane Mabire, were incredibly strong, capable, and determined women made for portrayal on the silver screen.

There are two primary heroes of this—as I must reiterate, entirely factual—story, both of them straight out of central casting. Jack Lee was the quintessential warrior: smart, aggressive, innovative—and, of course, a cigar-chewing, hard-drinking man who watched out for his troops and was willing to think way, way outside the box when the tactical situation demanded it, as it certainly did once the Waffen-SS started to assault the castle. The other was the much-decorated Wehrmacht officer Major Josef ‘Sepp’ Gangl, who died helping the Americans protect the VIPs. This is the first time that Gangl’s story has been told in English, though he is rightly honored in present-day Austria and Germany as a hero of the anti-Nazi resistance.

Harding, is a respected military affairs expert who has written seven books and long specialized in World War II, and his writing style carries immediacy as well as authority. “Just after 4am Jack Lee was jolted awake by the sudden banging of M1 Garands,” he writes of the SS’s initial assault on the castle, “the sharper crack of Kar-98s, and the mechanical chatter of a .30-caliber spitting out rounds in short, controlled bursts. Knowing instinctively that the rising crescendo of outgoing fire was coming from the gatehouse, Lee rolled off the bed, grabbed his helmet and M3, and ran from the room. As he reached the arched schlosshof gate leading from the terrace to the first courtyard, an MG-42 machine gun opened up from somewhere along the parallel ridgeway east of the castle, the weapon’s characteristic ripping sound clearly audible above the outgoing fire and its tracers looking like an unbroken red stream as they arced across the ravine and ricocheted off the castle’s lower walls.” Everything that Harding reports in this exciting but also historically accurate narrative is backed up with meticulous scholarship. This book proves that history can be new and nail-bitingly exciting all at once.

Despite their personal enmities and long-held political grudges, when it came to a fight the French VIPs finally put aside their political differences and picked up weapons to join in the fight against the attacking SS troops. We get to know Reynaud, Daladier, and the rest as real people, not merely the political legends that they’ve morphed into over the intervening decades. Furthermore, Jean Borotra (a former tennis pro) and Francois de La Rocque, who were both members of Marshal Philippe Petain’s Vichy government and long regarded by many historians as simply pro-fascist German puppets, are presented in the book as they really were: complex men who supported the Allied cause in their own ways. In de La Rocque’s case, by running an effective pro-Allied resistance movement at the same time that he worked for Vichy. If they were merely pro-Fascist puppets, after all, they would not have wound up as Ehrenhäflinge—honor prisoners—of the Fuhrer.

While the book concentrates on the fight for Castle Itter, it also sets that battle in the wider strategic contexts of the Allied push into Germany and Austria in the final months of the war, and the Third Reich’s increasingly desperate preparations to respond to that advance. This book is thus a fascinating microcosm of a nation and society in collapse, with some Germans making their peace with the future, while others—such as the Waffen-SS unit attacking the castle—fighting to the bitter end. (Some of the fighting actually took place after the Doenitz government’s formal surrender.)

The book also takes pain to honor the lives of the “number prisoners” who worked at Castle Itter—faceless inmates from Dachau and other concentration camps whose stories have never before been told in this much detail. Whatever their political leanings or personal animosities toward each other, the French VIPs did what they could to help the so-called “number prisoners”—i.e. the ones stripped of their names—in any way they could.

One of the honored prisoners was Michel Clemenceau, the son of the Great War statesman Georges Clemenceau, who had become an outspoken critic of Marshal Petain and who was arrested by the Gestapo in May 1943. At Castle Itter he showed “unshakeable confidence” in rescue, and had clearly inherited the courage of his father, who’d been nicknamed “The Tiger.” During the attack, with ammunition running dangerously low—they got down to the last magazines of their MP-40s—their tanks destroyed, and the enemy advancing from the north, west and east, this septuagenarian kept blasting away. His father would have been proud of him.

The story has an ending that Hollywood would love too: just as the SS had settled into position to fire a panzerfaust at the front gate, “the sound of automatic weapons and tank guns behind them in the village signaled a radical change in the tactical situation.” Advancing American units and Austrian resistance fighters had arrived to relieve the castle. In keeping with the immense cool that he had shown throughout the siege, Lee feigned irritation as he went up to one of the rescuing tank commanders, looked him in the eye and said simply: “What kept you?” Part Where Eagles Dare, part Guns of Navarone, this story is as exciting as it is far-fetched, but unlike in those iconic war movies, every word of The Last Battle is true.