The Original Adventures of Hank the Cowdog by John R. Erickson is narrated by Hank, a dog who serves as the self-appointed Head of Ranch Security on a cattle ranch. Hank is proud, boastful, and deeply committed to his role, though his confidence far exceeds his competence. He tells his story with the grandiose tone of a hard-boiled detective, even as events consistently undermine him.
Hank reports that a murder has occurred on the ranch. The night before, he patrolled the perimeter after hearing coyotes in the pasture while his assistant, Drover, a small white dog with a stub tail, stayed behind claiming a lame leg. Hank barked at the coyotes all night until Loper, one of the ranch's cowboys, fired shots increasingly close to Hank. At dawn, Drover wakes Hank with urgent news: The chickenhouse has been attacked and a white leghorn hen killed. Hank examines the scene but finds no useful evidence. Drover leads him to tracks by the creek that Drover identifies as coyote, but Hank insists the scent is raccoon and gives chase. He pounces on the creature in the bushes, only to land on a porcupine.
The porcupine leaves Hank's face and paws full of quills. He limps to the yard gate, where Pete the Barncat taunts him by flicking his tail across Hank's quill-studded nose. Loper scolds Hank for bothering the cat and eventually notices the quills, pulling them out with fencing pliers. The pain causes Hank to accidentally urinate on Loper, who throws the pliers at him. Sally May, Loper's wife, discovers the dead hen, and Loper lectures Hank about failing in his duties. That night, Drover sounds the alarm about an enormous horned monster near the chickenhouse. Hank attacks the creature, getting kicked and battered, only to discover Drover sent him into battle against the ranch's milk cow.
The next day, Loper and Slim, another ranch cowboy, drive their flatbed pickup to town, and Hank and Drover jump in the back despite orders. In town, they encounter Bruno, a hostile boxer chained in a neighboring pickup. Drover provokes Bruno by urinating on his tires, and Hank joins in after Bruno insults cowdogs. They wet all four tires, then pretend to be asleep when the cowboys rush out. Bruno is scolded by his master while Hank and Drover escape blame.
Back on the ranch, Hank hides with Drover in tall weeds near the chickenhouse for a stake-out, but both dogs fall asleep and a second hen is killed. Hank's mouth waters at the sight of the fresh chicken. He sends Drover away, carries the body into the horse pasture, and eats it. He wakes the next morning surrounded by white feathers, with feathers clinging to his mouth. Sally May stands over him, horrified. Loper ties the chicken head around Hank's neck as punishment.
Humiliated, Hank endures further indignities: Pete taunts him about his "necklace," and even Drover flees upon seeing the chicken head. Convinced the injustice is unbearable, Hank quits as Head of Ranch Security and heads north into the canyon country, imagining the ranch family searching for him. In the canyon, he encounters Wallace and Junior, a father-and-son pair of buzzards. Junior, who has a stutter, insists Hank is dead because he detects a signal, which turns out to be the rotting chicken head. Hank bargains with them: The buzzards can have the chicken head if they chew through the string. Wallace gnaws through it, but a chicken hawk steals the prize while the buzzards fight over it.
The next day, hungry and alone, Hank discovers a female coyote with her head stuck inside a Hawaiian Punch can. Despite the rule that cowdogs and coyotes are natural enemies, he pulls the can free and is overwhelmed by her beauty. She calls herself Girl-Who-Drink-Blood, but Hank renames her Missy Coyote. She warns him that her brother is Scraunch, the most notorious outlaw coyote in the region. Before Hank can leave, the whole coyote family appears, and he finds himself surrounded.
Chief Gut, Missy's father and the tribe's scarred leader, mocks Hank for entering the canyon without a cowboy or a gun. Scraunch advances with bared fangs. In desperation, Hank bluffs that he deliberately walked into the canyon as a trap, implying he holds a dangerous secret. The bluff works because coyotes are superstitious, and Chief Gut convinces Scraunch to stand down. However, Missy announces Hank must stay, become a coyote warrior, prove himself in battle, and marry her.
Hank settles into village life, gradually embracing the carefree coyote lifestyle. He befriends two brothers named Rip and Snort, who take him to an old silage pit where they eat fermented, mildly intoxicating silage and sing the coyote anthem. One night near ranch headquarters, Hank visits Drover, who tearfully begs him to come home, calling the coyotes "coyote trash" and declaring he will no longer run from danger. They part bitterly. Over the following days, Hank grows increasingly uncomfortable with the constant fighting, pups biting his tail, and a feast of rotten meat that makes him violently ill. Then Missy tells him Scraunch is organizing a raid on the ranch.
At dark, Scraunch delivers a fiery speech, noting that the ranch no longer has its big guard dog and suggesting they kill the small white one too. To test Hank's loyalty and desire to marry Missy, Scraunch orders Hank to accompany him to attack Drover directly. The raiding party approaches the ranch from multiple directions. Hank realizes Scraunch must have been the one committing the original chicken murders, slipping down to the ranch alone. As they creep within range, Hank sees Drover near the machine shed, shivering but holding his ground.
Something snaps inside Hank. He charges toward Drover, yelling at him to run, but Drover holds firm. At the last moment, Hank flies past Drover and attacks the coyotes, tackling Scraunch and biting off a piece of his ear. Scraunch orders the pack to attack together, and they wrestle Hank to the ground. Scraunch straddles him, preparing to tear out his throat, when Loper fires his shotgun from the back porch. The blasts scatter the coyotes. Only Scraunch retreats slowly, promising they will meet again.
Loper runs up the hill and smiles at Hank, something Hank cannot recall ever happening. He hugs Hank and says he is glad to have him back, though he notes Hank stinks. Sally May discovers Drover lying motionless, but Loper finds only minor injuries. They carry Drover to the house for a soft bed and warm milk. Hank catches Drover sneaking one eye open, realizing Drover is faking to enjoy the pampering. Drover milks the situation for two days before urinating on the carpet and getting thrown out.
When Drover returns, Hank claims his time with the coyotes was a top-secret undercover operation to crack the chickenhouse murder case. Already working a new case, he follows tracks into Sally May's yard and pounces on a creature in the flowerbed that turns out to be a skunk. The spray blinds him and drifts through an open window. Hank stumbles into the utility room, landing on Sally May's clean laundry, and she chases him out with a broom. Hank closes his account with a reflection on the demands of his job: the long hours, the danger, the ingratitude, and his acceptance that being misunderstood is all part of a cowdog's day's work.