The story opens with a letter to Breckinridge Elkins from his Aunt Saragosa Grimes, suggesting that his long-estranged cousin, Bearfield Buckner, might be softening his vengeful feelings toward Breck. However, her description of Bearfield’s threats makes it clear that things are still quite hostile.

Breckinridge is currently with a cattle drive in Colorado and is tasked by the suspicious Old Man Mulholland to head into the town of Antioch and buy provisions. On the way, Breck meets Professor Horace J. Lattimer, a flamboyant elixir salesman, traveling in a decorated buggy with his assistant Meshak (a cross-eyed Black banjo player) and a monkey. Shortly after, a man named Lem Campbell appears, claiming to be from nearby Gallego, and warns Breck that his cousin Bearfield is in town and has gone insane, obsessed with marrying a non-existent woman named Ann Wilkins.

Taking this bait, Breck races to Gallego to intervene, strongarms Lattimer and Meshak into following him with their elixir, and sends Lem with Mulholland’s money and chuckwagon to Antioch. In Gallego, Breck finds Bearfield in a saloon, very much sane, but wearing a wildly garish shirt and celebrating his impending wedding to—ironically—a very real woman named Ann Wilkins. Breck, thinking him mad, initiates a brawl and subdues Bearfield after a legendary melee.

Convinced Bearfield must be "cured," Breck hauls him to what he believes is Lem Campbell’s cabin and force-feeds him Lattimer’s quack elixir. The cabin, however, turns out to belong to Drooping Whiskers, an old, bow-legged rancher who returns to find his home occupied and is promptly run off by Breck.

Breck and Lattimer struggle to keep Bearfield restrained and medicated. Bearfield violently resists the elixir, breaking ropes and threatening death, but Breck continues the "treatment," despite growing exhaustion. Lattimer, increasingly terrified, abandons the situation during the night, taking the chuckwagon in exchange for the buggy that Meshak earlier stole while fleeing in terror.

Meanwhile, a mob from Gallego is closing in, seeking revenge against Bearfield for past beatings. Breck intercepts and scatters them with buckshot before falling asleep in the brush. When he returns to the cabin at dawn, he finds the wagon and elixir gone and Bearfield loose. Another massive fight breaks out, resulting in the destruction of the remaining elixir and the cabin’s interior.

Realizing he’s out of options, Breck decides to ship Bearfield back to Texas via train. At a railroad crossing, he flags down a train and bribes the conductor with his watch, chain, and pistol to take Bearfield to Dodge City.

Upon arriving in Antioch, Breck finds Old Man Mulholland enraged over the missing money and chuckwagon. Breck gets into yet another fracas with him and winds up inadvertently nearly drowning the man in a horse trough, creating a town spectacle. Just as Breck tries to explain the situation to the sheriff, Drooping Whiskers shows up, accusing him of theft and assault.

Matters take a further absurd twist when a telegraph arrives announcing that Bearfield has hijacked the train, forced the crew to reverse it, and is returning at full speed—still seeking to get married. A bystander then reveals that Ann Wilkins was real, but married Lem Campbell the day before with the very fifty dollars Breck had entrusted to him.

Breck, knowing Bearfield will kill him on sight, decides to flee again—“to save Cousin Bearfield’s life.” He rides south, eventually finding "restful" refuge in a Mexican revolution.