Maria meets Robert Jordan when he comes back to the cave with Pablo and Anselmo and she serves him dinner. Chemistry is instant. Lots of blushing.
While Maria's back in the cave and Robert Jordan's hanging outside with Rafael, Rafael tells him how the band recovered Maria when they blew up a fascist train some time ago. She was in really bad shape psychologically, and took a long time to recover.
Rafael also tells Robert Jordan that Pilar cares a lot for Maria, and is very protective of her.
When Robert Jordan talks with Pilar, he hears that he must be careful with Maria, who's quite affected by him. He proposes that, after the operation, he and Anselmo can take Maria away and find a place for her.
After the first confrontation with Pablo, Maria puts her arm on Robert Jordan's shoulder and talks with him a bit.
A little later that night, Maria, Pilar, and Robert Jordan have a conversation. Robert Jordan says he finds Maria beautiful and intelligent (how does he know this?).
When the talk turns to their fathers, Maria is struck by similarities between her father and Robert Jordan's, and declares that she and Roberto are "the same."
Maria goes to Robert Jordan's bedroll later that night, and gets in. She undresses.
Maria tells Robert Jordan she wants to be his woman, and that she hopes being with him will erase the memory of her rape. They have sex.
Maria leaves Robert Jordan before he wakes up. She serves breakfast. It's decided she, Pilar, and Robert Jordan will go to see El Sordo
On the way up to El Sordo's, Maria hears Pilar's story about the killing of the fascists in her town and is somewhat traumatized, though she'd asked to hear it.
Arriving at El Sordo's, Maria meets Joaquin, who's got a bit of a crush on her and reminds her that he carried her on his back from the train. When he begins to cry over his family, Maria kisses him, and says she is his sister.
On the way back down from El Sordo's, Pilar tells Maria that she is upset sometimes by how ugly she feels. She's jealous of Maria and Robert Jordan, in part because she cares so much for Maria. She tells them to go off on their own.
They do, and have sex in the heathers. The earth moves. Afterwards, Pilar tells them that happens only three times in one's life.
Maria returns to the camp with the other two. Eventually she serves dinner
Later that night, as she did the night before, she goes to sleep with Robert Jordan. Sex ensues.
Next morning, Maria wants to accompany Robert Jordan to the sentry post where he'll man the machine gun and keep an eye out for fascist patrols. He doesn't let her.
While Robert Jordan and company are at the machine gun, Maria stays in the cave, packing up the band's supplies in preparation for the escape the next day.
Later in the day, Maria brings Robert Jordan the letters left behind on the young officer's body that morning.
That night, Maria joins Robert Jordan, as usual, but she's in pain and unable to make love. They talk instead.
Maria tells Robert Jordan the details of what happened to her and her family when the fascists took over her town.
Maria remains blissfully asleep as Robert Jordan discovers Pablo's treachery and rages. When she wakes up, she's feeling up for getting it on. They do.
During the bridge operation, Maria is left to watch the horses while the others fight.
Maria makes it across the exposed patch of road on horseback. Robert Jordan does not.
After Robert Jordan is wounded, he urges the weeping Maria to leave him behind. She is very reluctant, and is pulled away by Pablo and Pilar.