Trench 11

Lieutenant Berton, a Canadian tunneller, digs 78 feet beneath a German position to rescue his fellow tunnellers. He accidentally startles a survivor, whose scream alerts the Germans above, who detonate charges and trap him underground for twelve days.

Three months after Berton's entrapment, Major Jennings and Dr. Priest debrief Colonel Ashcroft about Trench 11, a deep German bunker behind Allied lines. They believe it is used to develop chemical and biological weapons and urge a thorough investigation.

Ashcroft authorizes bringing Berton back from leave to assist the investigation. During his leave, Berton forms a romance with a French woman named Veronique, complicating his commitment to the mission.

Berton accompanies Jennings and Dr. Priest to Trench 11 with Captain Cooper, Sergeant Pronger, and Private Kelly. They prepare to locate the bunker and determine its purpose.

Inside the trench, the group finds dead German soldiers and evidence that Trench 11 had been shelled prior to their arrival. The scene signals a chaotic, dangerous environment beneath the front lines.

At German HQ, the 5th Army's high command orders Reiner and Mueller to erase all traces of the Wotan Complex. Reiner, known as 'The Prophet,' intends to finish what the Germans started with their weapons program.

Mueller escorts Reiner into the bunker to purge evidence. In the trench, a left-behind German soldier begs them not to open a sealed door; Jennings' team ignores the plea, and Cooper is forced to shoot the man.

Descending deeper, the group is attacked by crazed intruders who vomit and lash at them. Berton and Cooper are ambushed, Cooper is stabbed, and they force their way toward an exit while Berton collapses the tunnel behind them.

Meanwhile, the others reach a hospital-like room where Pronger is attacked by a crazed man. Dr. Priest performs an autopsy on a dead soldier and finds a worm crawling from the wound, concluding the worms are engineered.

Pronger and Kelly stage a mutiny and demand to leave; a brutal confrontation follows, and Jennings and Pronger are killed while Kelly and Dr. Priest are captured.

Reiner interrogates Dr. Priest, who explains the worms were meant to kill livestock and have jumped to humans. Reiner reveals his intention to use the parasite to destroy Europe and reshape it under German rule.

Kelly dies from the parasite and, in a bid to prevent further chaos, Berton shoots Kelly after a tense standoff with Mueller. Mueller's calm warns that releasing the parasite would be disastrous for everyone.

Mueller and Berton locate the charge chamber and discover the explosives were never rigged in the first place. Reiner orders the lower level sealed as he begins collecting parasites for his plan.

Berton and Mueller scramble to detonate the remaining charges. An infected attacker breaks Mueller's leg and destroys the clock timer, and Berton is shot in the leg by Reiner. After a brutal fight, the tunnel collapses; Berton kills the guard and staggers away, catching a vision of his lover Veronique with an ambiguous fate at the end.