Bret Harte's 1869 short story centers on the friendship of two men in the American West. They remain loyal buddies even after both are betrayed by a woman, who is an unfaithful wife to one and mistress to the other.

Tennessee, a gambler and thief, has a friend who is known as Tennessee's Partner. Such nicknames are used for newcomers in the town. (The judge called "Lynch" is another example.) After the woman rejects first one and then the other man, their friendship resumes.

When Tennessee is apprehended while fleeing after committing a robbery, Partner testifies at his friend's trial, but he then makes a mistake dealing with the judge, trying in vain to give him a bribe. Following the judge's sentence, Tennessee is hanged.

Tennessee's Partner takes his friend's body and buries it in a grave he dug outside his cabin. Eventually, Partner falls ill and dies, calling out to his friend from his deathbed.

The unnamed narrator explains that the real name of Tennessee’s Partner has—in accordance with Sandy Bar’s quixotic practice of rechristening new arrivals—never been known in the mining town. The locals have dubbed the man “Tennessee’s Partner” because he teamed up with Tennessee, a wholly disreputable character whose own real name has been similarly obliterated from communal memory.

The narrator goes on to relate the story of Tennessee’s Partner’s search for a bride. A year earlier, in 1853, the man set out for San Francisco from Poker Flat but got no farther than Stockton, where he was attracted by a waitress in a hotel. During a courtship, the waitress broke a plate of toast over Tennessee’s Partner’s head, then agreed to marry him before a justice of the peace. With his new bride in tow, the man returned to Poker Flat, and then went to Sandy Bar, where the couple took up residence with Tennessee.

Some time after his partner’s return, Tennessee began making indecent advances to the new bride until she ran off to Marysville. He then followed her there and set up housekeeping without the aid of a justice of the peace. A few months later their relationship ended; the woman took up with yet another man and Tennessee returned to Sandy Bar. To the disappointment of the townspeople, who gathered to witness a shooting, Tennessee’s Partner was the first man to shake Tennessee’s hand, and he greeted him with affection. With no trace of bitterness, and without apology, Tennessee and his partner resumed their former relationship as if the woman had never existed.

The narrator goes on to explain that the residents of Sandy Bar suspect that Tennessee—already known to be a gambler—is also a thief. These rumors are confirmed when Tennessee is caught red-handed after robbing at gunpoint a stranger traveling between Sandy Bar and Red Dog.

After frantically escaping from Sandy Bar, Tennessee is cornered in a canyon, where Judge Lynch finds him. Armed with a better “hand” than Tennessee—two revolvers and a bowie knife—the judge calls Tennessee’s bluff and takes him prisoner. During the ensuing trial, conducted by Lynch, Tennessee’s Partner tries to buy his friend’s freedom, offering a watch and seventeen hundred dollars in raw gold, his only belongings of any real worth. This offer is construed as a bribe, so rather than help the accused, it merely hastens his date with the “ominous tree” atop Marley’s Hill. Tennessee is convicted and sentenced to hang.

Tennessee’s Partner does not attend the hanging. Afterward, he arrives with a crudely decorated donkey cart and rough coffin to claim Tennessee’s body. Followed by a curious crowd, he drives the makeshift hearse through Grizzly Canyon to an open grave near his cabin. There he gives a brief, rustic funeral oration, thanks those in attendance, and buries Tennessee.

After this primitive funeral, the health of Tennessee’s Partner declines. He visibly wastes away until he takes to a sickbed and dies. In his final delirious moments, he envisions his reunion with Tennessee in death: “Thar! I told you so!—that he is—coming this way, too—all by himself, sober, and his face a-shining. Tennessee! Pardner!”