Robert Jordan surveys the geography of the area where his mission is to take place, flashing back briefly to the meeting with General Golz where he was given the assignment to blow up a bridge. He has two bags of explosives.
His guide Anselmo leads him up the mountain slope, where they meet Pablo. Robert Jordan doesn't like the look of Pablo. It doesn't seem like Pablo wants to help, but he agrees to lead Robert Jordan to his cave.
Robert Jordan arrives at the cave meets Rafael, Maria, and Pilar. He feels chemistry with Maria pretty fast. He gets a bit of background on Maria from Rafael. Pilar reads his palm and sees something there she doesn't like.
Robert Jordan goes to map out the bridge itself with Anselmo, and begins to appreciate what a good man he is. On the way back, he meets Agustín.
Back at the cave, where three of the other band members have arrived, Robert Jordan has a confrontation with Pablo, who has decided the band won't help him. Pilar comes to his support, and everyone else follows Pilar.
When he leaves the cave, Robert Jordan is approached by Rafael, who tells him he should have killed Pablo. Robert Jordan is not so sure.
Pilar confirms that he was right not to kill Pablo when he goes back into the cave. He also has a brief talk with Maria, who says that they are "the same."
Sleeping outside, Robert Jordan is surprised (or not?) by Maria, who climbs into his bedroll and takes off her clothes. She wants to be his woman and go with him after the mission is over, but he doesn't make any promises. They have sex anyway.
Robert Jordan awakens to the sound of planes, which is worrying. He orders Anselmo to do reconnaissance near the bridge and decides he will go see El Sordo and ask for his help. Pilar and Maria accompany him.
On the way up to El Sordo's, Robert Jordan gets to know Pilar better. She tells him the story of how the movement began in her town, and he is impressed by her skills as a storyteller.
The three of them arrive at El Sordo's. Although El Sordo speaks in a sort of pidgin Spanish to him at first, they get along well, and Sordo agrees to help. Also gives him some whiskey.
In the course of conversation at El Sordo's, it comes out that Robert Jordan had to kill his friend Kashkin to prevent him from being taken by fascists.
After they leave El Sordo's, Pilar tells Robert Jordan he should spend the afternoon with Maria. He does: they have sex in the heathers; the earth moves.
Back in the cave, it's snowing outside. Robert Jordan is anxious for Rafael to return so he can learn where Anselmo is and retrieve him. He's still out in the storm.
Fernando takes Robert Jordan to get Anselmo. They are very happy to see each other.
Robert Jordan returns only to be tormented by Pablo, who claims to be drunk. Robert Jordan doesn't think he is drunk. As tension grows, he prepares to kill Pablo, but Pablo leaves before anything happens.
When Pablo leaves, Robert Jordan confers with everyone else. Most of them want to kill Pablo, but Robert Jordan then realizes shooting around in the cave wouldn't be a good idea, because his dynamite is there.
As he works on sketching the plans to blow the bridge, Robert Jordan has a flashback. He thinks of his time at Gaylord's, of Karkov, and of the way he was "corrupted" at Gaylord's. His "education" began there.
Robert Jordan and Pilar get into a discussion about the supernatural, and whether one can see one's fate. Robert Jordan remains unconvinced by Pilar, and thinks it's all hocus pocus.
Robert Jordan and Maria have sex again outside in his sleeping bag before going to sleep.
In the morning Robert Jordan awakens to the sound of a fascist patrolman on horseback. He shoots the patrolman. But now the band needs to make sure no one followed him.
Robert Jordan goes to set up a machine gun some ways up the road from the cave with three of the others. A fascist patrol does come by, but doesn't follow the tracks of the patrolman back to the cave.
Agustín and Robert Jordan talk over lunch, and Agustín reveals that he too has been in love with Maria. Robert Jordan says he intends to marry Maria. Agustín wishes Robert Jordan the best, and agrees to help him however he can.
Fighting starts at El Sordo's, as Robert Jordan predicted. But he tells the others it would be a lost cause to help Sordo.
As the day passes, Robert Jordan reads through the papers of the young officer he killed, and thinks about whether it's right to kill.
The planes bomb El Sordo, and Robert Jordan stays in position to watch the fascist forces as they return from the battle site
Robert Jordan returns to the cave. After tallying the fascist forces that have been moving through the area in the last few days, he decides he must warn Golz that they are ready for the attack, and writes a dispatch to him. He sends Andrés with it.
Some time later, walking back from the sentry post where he saw Primitivo, Robert Jordan thinks about his life back home in America, and his father and grandfather.
Robert Jordan's back in the sleeping robe with Maria. But Maria doesn't feel up to having sex, so they talk instead. He learns the details of her abuse by the fascists, and is enraged. He tells her he intends to marry her.
Robert Jordan is awakened around two in the morning by Pilar, to be informed that Pablo has stolen the detonators.
Returning to his robe, Robert Jordan stays awake, simmering. After some time, Maria wakes up, and is feeling frisky. So they have sex one last time.
Robert Jordan gathers in the cave very early in the morning with the rest of the band, resigned to likely failure. He figures out how to set off the explosives with grenades instead of the detonators. Then Pablo comes back.
Everybody sets off for the bridge site, Robert Jordan among them. He leaves Maria behind with the horses a short way from the bridge.
The bombs fall, and Robert Jordan springs into action. He and Anselmo kill the sentries and rig the bridge. He waits for Pablo some time before blowing it up.
Since Pablo is a long time in coming, Robert Jordan blows up the bridge. Anselmo dies, upsetting him greatly.
He and Agustín set up the machine gun and wait for Pablo at the gorge. Pablo finally comes over, and they head back to meet the others at the horses.
Robert Jordan is wounded in the escape, breaking his leg. As he can't ride, he must be left behind.
It's hard to convince Maria to leave him, but Robert Jordan does, with some (physical) help from Pilar and Pablo.
All alone, Robert Jordan reflects on his life and fights the urge to kill himself and end his pain, steadily growing worse. He lies in wait for a victim, and Lt. Berrendo approaches his line of fire.