In the 22nd century, Earth has transformed into a vast tropical jungle, where only genetically modified animals have survived. Among them is Siboo-Boosh, an unconventional hunter-gatherer who lives on a diet of muffins and fruit. Fascinated by an ancient legend, he embarks on a quest for the 'Big Chunk,' a mysterious monolith. Naturally, his journey will be fraught with danger. Monki Buzzness, a malevolent being, unleashes hordes of hostile creatures to block his path.