Breckinridge Elkins is guilt-tripped by his formidable Aunt Tascosa into retrieving her drunken husband, Uncle Shadrach Polk, from a binge in the Apache Mountain settlement. She demands Breckinridge not only bring him back but also shock him into swearing off alcohol forever.

As Breckinridge heads out, he comes across some cousins painting a jackass (Joshua) in bright red, white, blue, and green. Inspired, Breckinridge decides to use the psychedelic donkey as a tool to terrify Uncle Shadrach into sobriety. He loads the slumbering, painted jack into a wagon and hauls him toward the settlement.

Along the way, he bumps into Kit Kirby, who is clandestinely meeting her suitor, Harry Braxton. The two lovebirds are forbidden by Kit’s tyrannical father, Buckner Kirby, to see each other due to a long-standing grudge against the Braxton clan. Breckinridge promises to help them elope by luring Buckner away from home with a fabricated tale of a gold strike in Wolf Canyon.

Breckinridge drops off Kit and prepares his two-pronged scheme: plant the jackass in Uncle Shadrach’s bed, and ensure Buckner chases the phantom gold strike instead of his daughter. But things quickly unravel.

Unbeknownst to Breckinridge, Buckner never heard the gold story and returns home to sleep while Breckinridge is still arranging things. That night, when Uncle Shadrach stumbles home drunk and lights a candle in his room, he sees the wildly painted Joshua in his bed. Screaming that he’s seen the Devil, Shadrach tumbles down the stairs—waking Buckner, who barrels out with a shotgun just in time to spot Kit and Harry eloping.

Breckinridge hastily convinces Buckner to give chase in a wagon, which ends in catastrophe as they take the wrong fork in the road and crash off a bluff. After surviving the wreck, Buckner turns on Breckinridge violently.

As Breckinridge recovers, he’s attacked by Uncle Jeppard Grimes and his large clan, who believe he kidnapped Joshua. A spectacular brawl breaks out, with Breckinridge fending off the Grimes boys in a melee of punches, pitchforks, and tree limbs, eventually using an unconscious cousin as a weapon.

Meanwhile, Joshua escapes and wanders into view, causing Jeppard to panic at the sight of his “bleeding” jackass. The Grimes clan deserts the fight to “save” him, and Breckinridge finally escapes the chaos.

When he checks in later, he discovers the gold-strike story he planted was stolen by Joel Garfield, who went off alone to claim the fortune, never alerting Buckner.

Returning home, Breckinridge finds that Uncle Shadrach is clinging to a jug of whiskey for dear life. The encounter with Joshua has convinced him that water causes hallucinations—since he hadn’t drunk all day prior to the sighting—and he swears never to touch it again.

Frustrated at the failure of his plan, Breckinridge attempts to forcibly sober up his uncle by dunking him in a horse trough. Aunt Tascosa, naturally, takes offense and spreads the rumor that Breckinridge tried to drown Shadrach for not swearing off liquor, thus ending the whole affair in more misunderstanding and ill will.