The Somme battlefield, 1916. A young engineer named William Livens watches in horror as the Lusitania sinks, believing his fiancée is aboard. In that moment, he vows to kill as many Germans as possible. His creation? A 56-foot-long flamethrower, a two-ton monster designed to spew burning oil 100 meters into enemy trenches. But before it could be used, a German shell buried it deep beneath the mud of No Man’s Land. Now, nearly a century later, a team of experts has just 15 days to find it.

Historian Peter Barton has spent years poring over Royal Engineers’ war diaries, and he’s uncovered a top-secret plan: a network of shallow tunnels, called saps, dug under No Man’s Land to deliver troops and weapons right to the German line. One of these, Sap 14, ran beneath a quiet field near Mametz. It contained explosives, a secret hatch, and the largest flamethrower of the war. “If we can find the parts of this, if they are still there, that is my Tutankhamun moment,” Peter says, his eyes alight with possibility.

The team—archaeologists Tony Pollard and Ian Banks, bomb disposal specialists, and Royal Engineers—assembles in northern France. But the field is a minefield, literally. “There is always the potential for munitions,” warns Gary Andrews, the bomb disposal expert. Every year, French authorities remove tons of unexploded shells from the region; over 600 bomb disposal officers have been killed in the line of duty. The danger is real, but the prize is irresistible.

They begin with geophysics, scanning the ground for traces of the trenches. A map from 1916 shows the British front line in black, the German line in blue, and Sap 14 in orange, snaking beneath No Man’s Land. The geophysicists pick up anomalies—a line that could be the sap. “There does appear to be a correlation between our mapping and the geophysics,” says one expert, cautiously optimistic.

With a machine, they strip away the topsoil. At first, nothing. Then, a shout: “Trench!” The team uncovers a stretch of the British front line, its walls packed with chalk—a deliberate backfill by farmers decades ago. “It’s like a neon sign,” Tony jokes. The trench is a time capsule. They find bullets still attached to a charger, a jar of Vaseline with fingerprints still visible, and a coin with a bullet hole through it. “That may have been a coin in somebody’s pocket,” Tony muses. “I wonder if that helped to deflect it, for good or bad.”

But the real target is the sap. The team believes the trench they’ve found leads to an incline—a staircase down to the tunnel. However, the war diaries note that the eastern entrance was blown up by a shell in July 1916. The western entrance might be intact. “If we can get in there, it would be an opportunity of a lifetime,” Peter says. The clock is ticking, and the ground is unforgiving.

As they dig, they uncover more: a French bayonet, evidence of the original French occupation; then, a grim discovery—human remains. “We’ve got a body here,” Tony says, his voice hushed. The bones are those of a soldier, possibly colonial troops who fought here in 1914. The team pauses to pay their respects, and the authorities are called. The excavation continues, but the weight of history is palpable.

Days pass with no sign of the sap. The team brings in a larger digger, but the clay is sandy and prone to collapse. “We’re floating because we don’t have these reference points,” Tony admits. Then, a breakthrough: at the eastern incline, they find a metal object—a valve from the flamethrower. “It’s flame projector, is it?” Peter exclaims. “There’s no doubt—it’s flame projector.” The piece is part number 280, a gate valve that controlled the flow of oil. “I’ve never seen anything else like it,” Peter says. “I don’t know of any part in any museum anywhere on Earth.”

The discovery sparks new hope. If one piece survived, more might be buried in the incline. But the rains come, flooding the site. With just days left, the team races to uncover the rest. “We’ve got a lot of work to do,” Tony says. The hunt for the flamethrower is far from over—and the secrets of Sap 14 are still waiting to be unearthed.

The eastern incline yielded its first treasure, but the western entrance remained the team’s best hope of reaching the sap intact. Day after day, the diggers scraped away at the clay, following the line of the trench toward where the map promised an entrance. Then, on the morning of day nine, a shout went up. “We’ve got timber—worked timber, straight edges, this is the frame of the incline!” Tony dropped to his knees, brushing soil away with a brush as if it were made of glass.

But the frame was empty. The tunnelers had stripped the timber from the shaft before abandoning it, and without support, the clay had collapsed inward. “They robbed it,” Peter said quietly, staring into the hollow. “They took everything they could reach and left the rest to the mud.” The western entrance, like the eastern one, was a dead end.

Yet the eastern incline still held secrets. As the team dug deeper into the shattered staircase, a metallic clink rang out. Gary, the bomb disposal expert, was on it in seconds. “Hold everything—everyone back, now.” The object was a shell, half-buried in the collapsed wall, its fuse still intact. The site fell silent. For an hour, the team waited at a safe distance while Gary and the French bomb squad worked. When the all-clear came, the relief was palpable—but so was the frustration. Another day lost.

That evening, Peter sat in the fines tent, turning the recovered valve over in his hands. “We have a piece of the machine,” he said, almost to himself. “But the machine itself—the monitor head, the fuel tanks, the pump—all of it is still down there, somewhere.” Tony, nursing a cup of tea, nodded slowly. “Then we go back to the incline. If the parts rolled down the chute when the shell hit, they’ll be at the bottom, in the sap itself.”

With just five days remaining, the team made a decision. They would abandon the search for the entrance and instead dig a fresh shaft straight down into the sap, guided by the geophysics. It was risky—the clay was unstable, and the deeper they went, the greater the chance of a collapse. But it was their only option. “We’re not leaving without the rest of that machine,” Peter declared.

The digger roared to life, biting into the earth. Meter by meter, the hole deepened. At fifteen feet, they hit chalk—the same chalk that had filled the trenches. At twenty feet, a layer of rusted corrugated iron. “That’s a roof,” Ian said, his voice tight. “That’s the roof of the sap.” The team held its breath as the digger carefully peeled back the iron. Beneath it, a dark void. Tony lowered a lamp into the opening, and the light flickered across a narrow tunnel, its walls lined with timber, its floor littered with debris.

“We’re in,” he whispered. “We’re actually in.”

But the tunnel was not empty. Half-buried in the mud at the bottom of the incline was a shape that made Peter’s heart stop—a long, cylindrical object, its metal surface pitted with rust but unmistakably part of a machine. “That’s the projection pipe,” he breathed. “Part number 321. The firing tube.” The team gathered around, their exhaustion forgotten. One by one, more pieces emerged from the mud: a section of the fuel tank, a bracket for the monitor head, a fragment of the pump.

But as they worked, a low rumble echoed through the tunnel. The walls trembled. “Get out!” Gary shouted. “Now!” The team scrambled up the shaft as a section of the tunnel collapsed behind them, swallowing the hole in a cloud of dust. When the dust settled, the entrance was gone—sealed by tons of clay.

Peter stood at the edge, his face pale. “We have the pieces,” he said, his voice shaking. “We have enough to rebuild it. But the rest of the machine—the rest of the story—is still down there.” Tony put a hand on his shoulder. “Then we’ve done what we came for. We’ve found the flamethrower.”

That night, the team gathered in the farmhouse that served as their headquarters, the recovered pieces laid out on a trestle table like relics from a lost civilization. The projection pipe, still caked with a century of Somme clay, stretched nearly the length of the room. Peter ran his fingers along its flanged edge. “Seven of these,” he said. “Seven firing tubes, each one feeding the monitor head. When the valve opened, the nitrogen forced the oil through all of them at once.”

Steve Boand, the Royal Engineer who had identified the first valve, picked up the bracket and turned it toward the lamp. “This is the mounting for the monitor head,” he said. “If we can fabricate the rest to match these dimensions, we can build something that behaves exactly like Livens’ machine—same pressure, same trajectory, same burn.” He paused. “Same terror.”

The room fell quiet. Tony broke the silence. “Then we rebuild it. Not as a museum piece—as a working weapon.”

Back at Chatham, the Royal Engineers’ workshops hummed with activity. Steve and his students worked late into the night, machining new parts to match the originals, welding the projection pipe onto a modern pump assembly, and testing the fast-acting shut-off valve again and again. “This valve is the heart of it,” Steve told Peter. “If it fails, the flame travels back down the pipe and ignites the fuel supply. Livens lost men that way in the early trials.”

Peter nodded, remembering the diaries. “He called them ‘death traps’ at first. It took him months to make it safe enough to fire from a tunnel.”

Meanwhile, Tony returned to the Somme with Ian and Gary to finish recording the site before the farmers reclaimed the field. The collapsed shaft had sealed itself, but the eastern incline still held one more secret. On the final morning, as they cleared the last of the shattered timber, Ian’s trowel struck something hard. “Tony—there’s a plate here. Stamped metal.”

Tony knelt and brushed away the clay. A rectangular plate emerged, its surface corroded but legible. “Part number 271,” he read aloud. “Monitor clamp. The one that held the firing head in place.” He looked up, grinning. “Peter’s going to want to see this.”

But there was no time left. The dig was over. The team filled the trenches, said their goodbyes to the farmer, and loaded the last crates into the vans. As they drove away, Tony glanced back at the field—flat, quiet, ordinary. “Ninety years from now, someone else will dig here,” he said. “I hope they find the rest of it.”

At Chatham, the rebuild was finally ready. The machine sat on the test range, its projection pipe angled toward a row of sandbags, its fuel tanks filled with five thousand liters of kerosene and diesel. Steve walked the line one last time, checking every connection. “Wind’s in our favor,” he reported. “Valve’s holding pressure. Torches are lit.” He turned to Peter. “Your call, historian.”

Peter looked at the machine—the machine he had chased across a century, through war diaries and geophysics and collapsing tunnels. “Light it,” he said.

Steve opened the valve. For a heartbeat, nothing. Then a roar like a dragon waking from a hundred-year sleep. The kerosene leapt through the torches and became a solid column of fire, arcing over the sandbags and slamming into the far berm in a bloom of orange and black. “Good grief—that’s burning my face!” Tony shouted, stumbling back as the heat washed over the observation party.

Peter didn’t move. He stood transfixed, the light flickering across his glasses, seeing not the test range but a trench in 1916. “That’s exactly like the photographs,” he said quietly. “Except now it’s in color.”

The flame guttered and died. Steve closed the valve, and the silence that followed felt enormous. The team looked at one another—archaeologists, engineers, historians—and then, slowly, they began to applaud. They had not just found a weapon. They had heard it speak.

Peter turned to the camera one last time. “William Livens built this to avenge a ship that never sank. Ninety years later, we gave his monster its voice back. History isn’t buried—it’s waiting.”

What would you have felt, standing in that field as the flame roared to life—terror, awe, or something in between?