Fred Chaney, portrayed by Goldthwait, is a straightforward bachelor whose life takes an unexpected turn when he inherits a peculiar buck-toothed horse named Don along with half ownership of a brokerage firm from his late mother. As Fred explores the implications of this surprising legacy, he learns that Don possesses a stunning ability – he can communicate with both humans and animals, including his own equine relatives in the countryside. Meanwhile, Fred’s stepfather, Walter Sawyer, played by Coleman, schemes to acquire Fred’s share of the brokerage for a paltry sum, but Fred stands firm in his decision to keep his inheritance.
Determined to maintain his hold on both the brokerage and Don, Fred embarks on a journey to reunite the horse with his family while also asserting his position at the firm, much to Walter's displeasure. As Fred settles into his new routine, Don quickly becomes an unexpected confidant, frequently seeking Fred’s counsel on a plethora of matters, including financial advice. To everyone's astonishment, Don demonstrates a remarkable talent for predicting market trends, leading Fred to amass a small fortune seemingly overnight.
With his newfound wealth, Fred rents a lavish penthouse and acquires a sporty new car. However, this success turns fleeting when Don starts to feign illness, prompting Fred to take the horse into his home as an unexpected roommate. Their growing bond reveals the deeper connections Don has with his family, especially as he grapples with the recent passing of his father, who urges him to find a mate to continue the line of talking horses.
At the stable, Don meets a beautiful white mare named Satin Doll, igniting a romantic interest. However, complications arise as Satin Doll happens to be a recent gift from Walter to his girlfriend, intensifying Fred's already convoluted situation. Fueled by envy over Fred's financial achievements, Walter enlists his secretary, Allison, played by Madsen, to uncover the mysterious source of Fred's success.
In an awkward date, Fred unwittingly discloses Don’s role in his financial prowess, but Allison misreads his seriousness as a joke. He insists on the truth and brings her back to their apartment, only for Don to remain silent about his unique gifts. A chaotic party ensues, attended by an array of animal guests, resulting in a wild mess that strains Fred's relationship with Don.
Feeling disillusioned with Don's antics, Fred finds himself reevaluating their companionship. However, inspired by the oats’ delightful aroma, Don suggests a new investment opportunity. Despite initial hesitations, Fred follows this advice, only to run into trouble as Don's health deteriorates from tainted oats, and Walter learns of a looming disaster concerning that investment. In a calculated move, Walter locks Fred in the bathroom before he can cash out, leaving him facing financial ruin.
Allison, realizing Walter’s deceit, decides to leave her position in protest. Upon encountering Don for the first time and learning about his abilities from Fred, she chooses to help the horse reunite with his family. Together, they plot their revenge against Walter by preparing to enter Don into a prestigious horse race against Walter's prized stable, which includes Satin Doll, who is now entangled in their rivalry.
Fred cleverly provokes Walter into betting his entire stable against Don’s success, stoking the flames of competition. With no jockey available, Don must rely on Fred's inexperience to steer him through race day. As the race nears, Don’s confidence wavers until he receives a motivational visit from his father, who now exists as a horse fly and delivers an uplifting speech about overcoming obstacles. Even with his new limitations, Don finds the strength to compete.
As the race begins, Don initially falls behind but showcases his strategic thinking, cleverly persuading most of his competitors to withdraw. As fatigue sets in among the final contenders, Don rallies against only Lord Kensington, the top horse from Walter’s stable.
Fred struggles to rally Don for a last-minute surge, but the allure of cosmetic dental work spurs Don into a blistering final dash. In a nail-biting finish, Don crosses the finish line first, flashing his glorious smile, as confirmed by the judges, culminating in a humiliating defeat for Walter. This spectacular race outcome brings joy not only to Fred but also to Don, as they both achieve their dreams of love—with Don winning over Satin Doll and Fred getting closer to Allison.
The film wraps up on a high note, showcasing Don’s delight in his new dental care, and concludes with the beloved Porky Pig's catchphrase: > "That's all folks."
