Colonel Gerineldo Márquez has had it up to here with the war. It used to be awesome, what with the blood and guts and idealism, but now he's totally over it.
Instead, he starts up with Amaranta again. Or at least, he tries to start it up, but she is totally grossed out by how old he now is, and ends it forever.
Actually, it's not just that Gerineldo has become tiresome; it's also that Amaranta realizes that little Remedios is now growing into the most beautiful woman that Macondo has ever seen. She starts getting crazy jealous all over again. Shmoop's armchair diagnosis: better to shut down the Gerineldo thing right away than risk another Rebeca-Pietro Crespi situation.
Colonel Aureliano Buendía comes back to town.
The war has taken all the human being out of him. It's so bad that he now has a ten-foot circle drawn around him at all times: no one can come inside. His absolute power has corrupted him absolutely.
It's been a gradual decline. First the widow of General Moncada closed the door in his face when he tried to return the General's things. In response, he burned down the whole house (presumably with her inside it).
Then he has a young up-and-coming dude from his own side assassinated for being too awesome.
Next, people start trying to make him happy by killing off whoever is presumably making him unhappy.
Finally, in the last piece of the crazy-dictator puzzle, he becomes totally paranoid of everyone around him.
While he hangs out in Macondo, a delegation of Liberals comes to see him (remember, that's his side of the war) to get him to sign some concession agreements for the Conservatives.
Basically the Liberals are now appeasing the Conservatives to try to hang on to their political power.
Signing this means totally renouncing everything he's ever stood for, but sure, what the heck, he just doesn't care anymore.
Colonel Gerineldo Márquez is again sentenced to death.
Colonel Aureliano Buendía kind of just shrugs it off, even when Úrsula comes to ream him out.
But that night, he gets back a little bit of his old self, rescues Gerineldo, and starts his last military campaign of the war: trying to get the government to sign a peace agreement that includes decent treatment for the rebels.
It's the bloodiest, most horrible campaign of all, partly because he has to kill a lot of his own men to get the peace agreement through.
When the treaty is finally about to be signed, he comes back to the house.
Everyone is psyched to have crazy old uncle Aureliano back, but it's as they'd hoped. He has totally lost all ability to love, feel, have memories, and in general, be a person.
He burns every single thing that marks him as having existed: all photos, all his writings, everything. Then he asks his doctor to draw an outline of where his heart it on his chest. Uh oh, we have a bad feeling about that.
Colonel Aureliano Buendía goes and signs the treaty. It's depressing and horrible, since it's a total renunciation of most of his life's work. The he shoots himself in the heart…
But he survives!
Turns out the doctor had a bad feeling, too, and drew the heart in a place where the bullet wouldn't graze any internal organs. Anatomically improbable, but whatever, it's clearly awesome.
He goes home to convalesce and starts to feel better.
Úrsula, meanwhile, sets the house in order again.
While she is bustling about like she always does, she asks the government soldiers guarding Colonel Aureliano Buendía to help her out.
As they start to do domestic tasks instead of just their soldiering, we get a nice little window into how fighters slowly transition back into domestic life after war.
Oh, and then we are told that one of them will eventually kill himself after Remedios the Beauty turns him down.