An isolated American battalion fights to hold a vital mountain stronghold in Italy, known as "Battle Mountain". But the Germans won't give it up without a fight; with artillery and infantry hammering their positions, US troops hole up in a decaying castle on the summit, relying on individual acts of bravery to keep the enemy from overrunning them.

As the war nears its end, an unorthodox, top secret commando unit launches a nighttime raid on a shallow lake in Northern Italy, to divert German forces from the next major Allied offensive. Led by Danish Major Anders Lassen — a fearless, hard-drinking brawler with an amphetamine addiction — they find themselves pinned down in unforgiving terrain, and must push through murderous German opposition, while the fate of the entire Allied assault hangs in the balance.