Colomba is a story about justice and revenge. It begins with an English girl and her father on vacation in Italy. The girl, Lydia, was unimpressed by Italy, and she looks forward to seeing Corsica along with her father, who wants to hunt there. Aboard a boat on the way to Corsica, they meet Orso de la Rabbia, a soldier in Napoleon's army who is returning home. Immediately, the Englishman (who fought on the opposite side of the war) and Orso have a respect for one another. When they arrive in Corsica, they are met by Colomba, Orso's sister. The Englishman invites them both to dine with him.

Colomba tells the Englishman and his daughter—Sir Thomas Nevil and Colomba by name—about Barricini, a lawyer whom she thinks murdered her father. She explains that there was a journal, kept by her father, in which the murdered man wrote the name of the culprit. Colomba believes that Barricini intercepted the notebook and wrote the name of a known bandit, Agostini.

The feud between the Barricini and the della Rabbia families was long-standing, and Colomba is determined to have revenge. A prefect decides to try to intervene and mediate between the two families, but when Orso discovers evidence that the bandit was likely paid off to take the blame for his father's fall, he becomes infuriated.

Orso challenges Barricini's son to a duel, and Colomba cuts the ear off of her brother's horse and blames the sons. Orso kills them in an ambush. He is accused of murder but acquitted, as he is found to have acted in self-defense. He moves to Italy with Colomba, and marries Lydia Nevil. One day, Colomba sees an almost unrecognizable Barricini in Italy and becomes enraged when he confesses that he had indeed torn the page from her father's notebook. She also realizes that he will not live long, but she has no sympathy for him.