A small group of American soldiers find horror behind enemy lines on the eve of D-Day.
Of the American soldiers, only Boyce, Tibbet, and Rosenfeld survive, along with helpful French citizens Chloe and her younger brother. Ford sacrifices himself to blow up the Nazis’ lab with mutated victims and all of their research. Boyce tells his superiors that they didn’t find anything in the lab, to prevent anyone else from discovering the Nazis’ plans.
Near the end of World War II, a team of paratroopers are sent to take down a Nazi radio tower. Their plane is shot down, and the surviving soldiers meet a French woman named Chloe who brings them to her home to hide from the German soldiers. They manage to capture a Nazi captain named Wafner who tries to rape Chloe but is subdued and captured.
Private Ed Boyce is sent out by Corporal Ford to locate the tower. Boyce ends up discovering a lab beneath the church where the tower is located where a Nazi doctor named Schmidt is conducting experiments to reanimate the dead, specifically Nazis, in order to ensure that the Nazis may reign supreme for centuries. Boyce rescues another soldier named Rosenfeld and brings back a sample of the serum. He uses it on his comrade Chase after he is killed by Wafner, but the serum causes Chase to have super strength, immunity to bullets, and uncontrollable rage as he mutates. This forces Boyce to crush Chase’s head. Wafner escapes and kidnaps Chloe’s brother Paul, forcing the soldiers to head out and take down the tower for good.
Wafner injects himself with the serum and turns into an inhuman abomination. Chloe manages to rescue Paul as the paratroopers take out the German soldiers. Boyce kills Schmidt while Wafner almost kills Ford. Ford decides to stay behind and detonate an explosive to destroy the tower and the lab. Ford blows himself and Wafner up as Boyce gets out.
Boyce reports to his superiors on the tower’s destruction but does not mention the lab or the experiments.
1944 – A team of paratroopers led by Sergeant Eldson (Bokeen Woodbine) are heading into Germany with orders to take down a Nazi radio tower from a church. Just as they near their target, their plane is shot at by enemy soldiers. The surviving men jump from their plane before it explodes, and they land in the water before swimming to land.
Private Ed Boyce (Jovan Adepo) reunites with Corporal Ford (Wyatt Russell). Boyce spots Eldson being found by a group of Nazi soldiers and sees as they execute him. Ford keeps Boyce quiet as they move and find Tibbet (John Magaro), Chase (Iain De Caestecker), and Dawson (Jacob Anderson). They walk toward their mark, and Dawson accidentally steps on a land mine that blows him up. The others keep moving into the woods as they spot a French woman named Chloe (Mathilde Ollivier) walking by. Ford orders them to run after her since nobody can know they are there. The men catch up to her, and Boyce speaks to her in French to let her know they mean no harm. Chloe reluctantly lets the men follow her back to her home.
Chloe leads the soldiers into her village when a neighbor hears her and calls to the German soldiers for her being out past her curfew. Chloe talks to the Germans while the American soldiers stay hidden. She brings them back to her house where she lives with her kid brother Paul (Gianny Taufer) and Aunt Simone (Eva Magyar), who is terribly ill and is heard making an unpleasant and loud wheezing sound. The men hide up in the attic. Paul wants to play catch with Tibbet, but he coldly brushes him off before he and Chase go check out the rendezvous site. Outside, German soldiers take a man and woman outside and execute them. Chloe says this is what happened to her own parents.
Chloe tends to Boyce’s bullet wound as she explains what happened to her family. Boyce also plays with Paul a little bit. Moments later, more German soldiers arrive for an inspection. They are led by Captain Wafner (Pilou Absaek). Boyce has to hide again as Chloe lets him enter her home. Wafner attempts to rape Chloe, but Boyce comes out and attacks Wafner, and the soldiers keep him tied up in the attic.
Ford sends Boyce out to find the rendezvous point. He comes across the church where the tower is located, but he is nearly spotted and is forced to hide in a truck filled with corpses of the other paratroopers. Boyce finds himself inside the church, and he comes across a laboratory where he sees a number of horrific discoveries, such as the head of a woman separated from her body but still speaking to him, as well as a bag with a barely living thing inside. Boyce hides and sees the mastermind, Dr. Schmidt (Erich Redman), entering. Boyce finds a fellow paratrooper named Rosenfeld (Dominic Applewhite) and pulls a massive needle out of him to save him. Boyce also takes with him a needle containing some kind of experimental serum before he and Rosenfeld flee.
Boyce brings Rosenfeld back to the attic and shows Ford the serum. He questions Wafner as to what it does, but he refuses to say anything, so Ford starts beating the crap out of him. Boyce explains to Ford what he saw in the church, so Ford starts to devise a proper plan to make their way in and take the tower down.
Ford orders Chase to go upstairs to untie Wafner so that he can get them inside. Wafner then attacks Chase and grabs his gun, shooting him repeatedly. Everyone runs upstairs to subdue Wafner, but while they try to help Chase, he ends up dying. Boyce grabs the needle and injects Chase with the serum. He soon comes back to life, but very quickly, he displays signs of enhanced strength and disorientation. Chase then starts to mutate horrifically and become violent. He attacks his comrades, forcing Ford to shoot him repeatedly. This doesn’t kill Chase, so Boyce has to smash his head to bits in order to kill him for good. Wafner says that is what the serum does and is essentially being developed by the Nazis to reign supreme for a thousand years. Wafner then manages to escape as his comrades are outside, and he kidnaps Paul and gives him to the soldiers. Ford and his men fire at the Germans, and Wafner gets half his face shot off as he gets out. Ford then decides they have to take down the tower immediately, with Paul’s rescue being second priority. Boyce and Chloe don’t like this, so they plan to rescue Paul first.
Wafner returns to the lab and finds Schmidt. To Schmidt’s horror, Wafner takes two needles with serum and injects himself, causing a rapid mutation and making him grow increasingly mad.
The Americans use a German soldier that they strapped with explosives to make their way into the church. Tibbet and Rosenfeld stay outside killing soldiers while Boyce, Ford, and Chloe head inside. Chloe is almost attacked by a soldier who tries to get her killed by one of the mutated people. The mutant kills the soldier and goes after Chloe, but she burns him to death with a flamethrower. She manages to get Paul out, but they still come under fire by the Germans.
Tibbet manages to get Paul through the gunfire, but is wounded himself. Meanwhile, Boyce and Ford encounter Schmidt and the mutated Wafner, who attacks them. Boyce fights Schmidt as he tries to stab him, but Boyce manages to kill Schmidt. Wafner then gets Ford and impales him on a meat hook. Boyce distracts Wafner as Ford frees himself and injects himself with the serum to fight Wafner. Before Wafner can get Ford, Boyce throws a tank and shoots it, causing an explosion. Boyce tries to help Ford out, but he chooses to stay behind and ensure that the laboratory is destroyed along with the tower. Ford gets an explosive ready as Wafner prepares to attack. Boyce runs out as Ford detonates the explosive, killing himself, Wafner, and every last mutant in there as the whole place goes down. Boyce reunites with the others outside and confirms that Ford is gone, while Chloe tends to Tibbet’s bullet wound.
Boyce later reports to his superiors on the mission, stating that Ford chose to detonate explosives from inside the tower to ensure that it went down. He also chooses not to mention a thing about the lab or the experiments. The superior then tells Boyce that he and his men will be reassigned.