Stu Miley, a brilliant and eccentric underground cartoonist, achieves mainstream success with his dark, subversive creation, Monkeybone, a mischievous, anarchic primate who voices Stu’s deepest, most chaotic id. Stu's professional triumph is paralleled by his personal bliss; he is deeply in love with Dr. Julie McElroy, a sleep specialist who appreciates his complex psyche. However, Stu's world abruptly shatters when a freak accident leaves him trapped in a deep, unresponsive coma.His consciousness is instantly hurled into Down Town, a surreal, neon-drenched purgatory populated by bizarre mythological creatures, urban legends, and the manifestations of human nightmares. Here, Stu is reunited with his creation, Monkeybone, who has mysteriously materialized into a sentient, hyperactive entity of flesh and fur. While Stu desperately searches for a way to return to the waking world and Julie, Monkeybone harbors a selfish, cunning agenda. Craving true independence and the physical pleasures of the mortal plane, Monkeybone schemes to steal Stu’s identity.Back in the real world, Julie utilizes an experimental machine designed to monitor Stu’s brain activity, inadvertently creating a vulnerable bridge between the living and the comatose. Seizing this golden opportunity, Monkeybone steals a valuable "pass" and hijacks the body of a recently deceased, comatose gymnast, launching himself into reality.Stu awakens in Down Town to the horrifying realization of Monkeybone’s betrayal. Trapped in the ethereal realm, Stu discovers he must find a way back before Monkeybone permanently locks him out of his own life. Teaming up with Miss Kitty, a feline femme fatale who is also disillusioned with Down Town, Stu navigates the chaotic, shifting landscapes of the afterlife, dodging terrifying monsters and bureaucratic nightmares.Meanwhile, Monkeybone wreaks havoc in the real world, misusing Stu’s body, ruining his
professional reputation, and attempting to seduce Julie. The chaotic primate plans to unleash a synthetic nightmare serum at a massive
Halloween party, which would permanently trap all mortals in Down Town while leaving Monkeybone free to roam Earth forever.Stu manages to breach the mortal veil, possessing various objects and eventually confronting his mischievous creation at the chaotic gala. A frantic, slapstick-infused climax ensues across a towering carnival ride. Stu outsmarts the primate, outmaneuvering his chaotic tricks. Ultimately, Stu defeats Monkeybone, reclaims his physical body, and snaps back to consciousness just as Julie reaches him. Having faced his literal and figurative inner demons, Stu returns a changed man, ready to embrace life, art, and Julie with newfound maturity.