Robert Jordan quits being a College Professor to fight with the Republicans in the Spanish Civil War.
Robert Jordan is instructed to blow up a bridge by General Golz
Robert Jordans guide, Anselmo, takes him to meet Pablo. Robert doesn't like Pablo, but allows him to lead him to a cave where the others are staying.
Robert maps out the bridge with Anselmo.
Robert and Pablo get into a confrontation. Everyone else sides with Robert. Rafael tells Robert that he should have killed Pablo, but Robert doesn't think that what would be best.
Maria comes outside to tell Robert that she loves him and that she wants to be his woman after the war. Robert also confesses his love but says he won't promise a relationship.
Robert Jordan is woken by Planes, so he decides to go ask El Sordo for help. Maria and Pilar accompany him.
Robert and Pilar get to know each other better. They meet El Sordo who agrees to help. Robert also reveals that he has to kill his friend Kashkin. Afterwards, Maria and Robert spend time together.
Robert waits in the cave for Refael to return so he can find Anselmo, who is out in the storm. Fernando takes Robert out and they find him.
Robert returns to the cave and Pablo starts harassing him. Pablo claims that he is drunk but Robert doesn't believe him. Robert prepares to kill Pablo, but Pablo leaves before anything can happen. Most of the people in the cave want to kill Pablo, but Robert realizes that shooting around explosives is a bad idea.
Robert is woken by a fascist patrol on a horse. He shoots the patrolman. After making sure he isn't followed, Robert sets up a machine gun away from the cave.
Agustín tells Robert that he also loves Maria. Robert tells him he plans to marry him and Agustín gives his blessings.
Fighting begins at El Sordo's and Fascist planes bomb them. Robert decides not to help
After tallying Fascist forces, Robert decides to warn General Golz that they are ready to attack the bridge. He sends Andrés to deliver the message.
Robert is woken up by Pilar who tells him that Pablo stole the detonators for the bridge explosives.
After resigning to likely failure, Robert figures out he can detonate the explosives with grenades instead.
Everybody sets off for the bridge site. Robert leaves Maria behind with the horses away from the bridge. Robert Jordan and Anselmo kill the sentries and rig the bridge. He waits for Pablo some time before blowing it up. Anselmo dies, upsetting him greatly. Robert and Agustín set up the machine gun and wait for Pablo. When Pablo arrives they meet the others at the horses.
Robert breaks his leg while escaping, and since he can't ride a Horse, he has to be left behind. He has a hard time convincing Maria to leave him, but does in the end. Robert Jordan is left alone and reflects on his life. He debates committing suicide, but decides to stay alive to fight off the Fascists.