In late 1944, during the Lapland War, prospector Aatami Korpi lives alone with only his horse and his faithful dog in the remote wilderness of Lapland. Aatami spends his days panning and mining in search of gold. After uncovering a rich deposit, he collects a hefty amount of gold nuggets and mounts his horse, heading for the nearest town with his dog in tow.

Along the way, Aatami encounters a 30-man Wehrmacht platoon led by ruthless SS Obersturmführer Bruno Helldorf and his subordinate Wolf, who are destroying settlements in their retreat and have taken several women captive. Bruno takes little interest in Aatami, letting him pass. Aatami is soon accosted by a second group of soldiers who discover his saddlebags full of gold and prepare to execute him and his dog, but he swiftly kills them all. Alerted by the gunfire, Bruno investigates and discovers the carnage. He finds one of Aatami’s gold nuggets, taken by one of the dying soldiers.

Bruno and his tank pursue Aatami to the edge of a minefield, where Aatami’s horse is obliterated by a mine. Gathering up his gold, Aatami intentionally detonates another mine to make his escape. The soldiers sent after him are quickly claimed by the minefield. Two of the captive women are ordered ahead to ensure a clear path. One of the captives, Aino, volunteers to take the place of one of the women and leads the way.

Retrieving Aatami’s dog tag, Bruno learns that he was once a Finnish commando who lost his family and home fighting against the Russians during the Winter War. Left with nothing, the vengeful Aatami became a legendary “one-man death squad” nicknamed Koschei. Bruno ignores the warning, defying orders to turn around and cease following Aatami.

Wounded and exhausted, Aatami is awakened by the platoon’s approach. With the soldiers’ dogs on his trail, he hangs underneath one of the German vehicles and punctures the fuel tank, dousing himself in gasoline to hide his scent. When the platoon halts to inspect the leak, Aatami flees, holding the dogs at bay by lighting himself on fire before diving into a nearby lake. Waiting for him to surface, Bruno sends soldiers into the lake, but Aatami slits their throats underwater and breathes in the escaping air from their necks. Aatami reaches the other side of the lake, but Bruno finds his dog.

Aatami discovers the town has been left in burning ruins by the Germans, and takes shelter in a petrol station. Bruno sends Aatami’s dog to find his master, with a lit grenade attached to his collar. Aatami saves the dog but is subdued by the explosion. Bruno, Wolf, and tank driver Schütze hang Aatami from the petrol station’s sign, taking the gold and leaving him for dead, but Aatami hooks his wounds onto protruding rebar, saving him from the noose. A pair of German pilots land in search of fuel. Aatami kills one and knocks the other unconscious.

Unwilling to face the consequences of Germany’s impending defeat, Bruno intends to use the gold to escape with Wolf and Schütze, arranging for a pilot to fly them to safety while the rest of the platoon makes their way to Norway. Meanwhile, Aatami forces the surviving pilot to fly him towards the platoon. Soon, the soldiers discover the airplane crashed in their path, with the pilot hanged by the same noose Wolf used on Aatami. As the convoy continues, Aatami climbs on and arms the captured women. He and Aino commandeer one of the trucks, allowing him to leap onto Bruno’s tank while the women gun down the rest of the soldiers.

Pulling Wolf out of the tank, Aatami leaves him at the mercy of the women and follows Bruno, who callously kills Schütze before taking off with the pilot. Aatami fires on the plane, mortally wounding the pilot, and uses his pickaxe to hack his way onboard in midair. After engaging in hand-to-hand combat with each other, Bruno brutally beats Aatami with a static line, subduing him. As Bruno is about to wield another set of blows, Aatami swiftly hooks the static line to a bomb, dropping Bruno to his death. With the pilot also dead, Aatami straps himself in as the plane crashes into a large swamp. Led by Aino, the women deliver Wolf and the Nazi tank to a speechless and incredulous Finnish army.

Still alive, Aatami escapes the swamp, reunites with his dog, and makes his way to war-ravaged Helsinki. Bloody and battered, Aatami enters a bank where he dumps his gold nuggets on the counter. He finally speaks, asking the teller for large bills, explaining they won’t be as heavy to carry as the nuggets.