The Story starts in 1937, Spain. The Spanish Civil War is raging between the Republicans and the Fascists. Anselmo (left), Robert (middle), and Pablo (right) make their way up a mountain to prepare to blow up a bridge controlled by fascists. Pablo, the leader of a guerrilla camp, is against the idea and is rude to Robert.
The group set up a camp in a cave in the mountains and are introduced to more people in the guerrilla camp, like Pilar and Agustin. Maria is also introduced, which is Robert's love interest. The group quickly loses faith in Pablo. They continue to plan to attack the bridge. They get support from El Sordo.
They all continue to camp at the cave. Plans to attack the bridge continue, but Pablo becomes more and more resistant. Arguing ensues, but Pablo refuses to fight Robert. The group discusses killing Pablo but his attitude quickly changes, causing them to believe he overheard them.
A fascist soldier rides into their camp, leading to Robert killing him. This marks the beginning of the violence. Robert orders preparation for defenses. El Sordo's camp is attacked by Fascists; they are all bombed and killed.
As the day comes to attack the bridge, Pablo steals some dynamite to blow up the bridge and runs away. Pilar fails to stop him. The mission will be more difficult but Robert plans to continue. Pablo eventually returns with more soldiers. He explained that he got rid of the dynamite but was guiltridden, so he returned.
The group finally attack and blow up the bridge, with the only survivors being Robert, Maria, Pilar, Pablo, and Agustin. As they retreat, a bullet hits Robert's horse, causing it to throw him off and trample his leg. He tells the other to leave him behind. As he lays there dying, the lieutenant that killed El Sordo's people appears. Roberto takes aim...