Napoleon Jamie Croft is a playful puppy living in Sydney who calls himself Napoleon and pretends to be tough, dreaming of the wild dogs and the distant howls he imagines he could hear if he ever left his human family. He hops into a birthday party basket with balloons, hoping to escape into a life of bravado, but his curiosity backfires when the basket drifts away, taking him far from home.
Birdo Philip Quast, a chatty galah, swoops in to lend a hand, but his idea of help is to pop the balloons so Napoleon can land safely on a beach. From there he journeys into a nearby forest, stubbornly determined to live among the wild dogs, even as Birdo warns him to return home. In the darkness of the trees, a tawny frogmouth Reg E. Cathey murmurs warnings of the dangers that await pets in the wild, but Napoleon presses on, briefly entangled in a spider’s web and then hunted by a large cat Geoffrey Bateman who mistakes him for prey. The cat’s menace is thwarted when the frogmouth pushes the cat into a pond, though she swears revenge as she slinks away.
The next day brings a chorus of distractions: rainbow lorikeets mock him from the trees and a rude koala adds to his woes. Napoleon reunites with Birdo, who agrees to teach him how to survive the wild, and he reveals his real name Muffin. Taunted by the snide commentary of a green tree frog and the noisy lorikeets, Napoleon finds himself stranded on a floating log, and only then does Birdo commit to guiding him into the wild. Their early lessons begin with swimming back to shore in a lake, a step that proves harder than it seems.
Napoleon’s education continues as he experiments with hunting, attempting to catch a group of rabbits and instead feeding on moss when he goes hungry. Birdo’s lessons about friendly versus dangerous animals broaden to encounters with a wombat and the badly injured quokkas, a reminder of the brutal realities of the wild he’s trying to join. A stampede of brumbies nearly derails the lesson, and Birdo misreads the scene as blinding snow and freezing fog, ultimately leaving Napoleon frustrated and momentarily alone. A scent of sweetness lures him toward a sugarcane field, despite Birdo’s caution about the dry, dangerous landscape. A snake warns him of danger just before a bushfire erupts, and they escape together with Birdo’s help. The cat resurfaces, but Napoleon ultimately outwits danger and reunites with a lost flock, only to be driven away again by the frill-necked lizard that blocks his view on the road.
The journey takes a tender turn when Napoleon helps an echidna find water and seek shade, and in a quiet moment, he realizes that the howling he’s been hearing is not a real pack, but a perentie lizard mimicking others. A torrential rainstorm arrives and floods the area, forcing Napoleon to seek shelter. He discovers two dingo puppies, Sid and Nancy, hidden in a damp cave, and when the flood waters sweep Nancy away, Napoleon dives to rescue her. The mother dingo returns, and Napoleon understands that he has found a new family among the wild dogs. The mother’s gentle counsel reassures him that courage has guided him here, affirming that the true spirit of the wild is measured by the bravery he already showed in saving Sid and Nancy.
Yearning for home yet again, Napoleon travels across the landscape in a kangaroo’s pouch, finally reaching the shore where his basket is occupied by a feisty penguin named Conan who longs to be wild and brave in his own right. Conan’s boisterous family arrives, and Napoleon’s plan to sail back to Sydney is interrupted when the cat returns. A confrontation erupts; Napoleon repeatedly thwarts the cat, but the decisive moment comes when Conan taunts the cat, distracting her long enough for Napoleon to shove her off a cliff and into the basket. The basket sails away as the sun glints off a distant horizon, and Napoleon glimpses a silhouetted image of a wild dog howling on a cliff—an emblem of the bravery he has finally embraced.
Birdo reappears with a sea turtle to guide Napoleon back toward home, and the journey ends with his return to Sydney. His mother welcomes him back and, moved by his adventures, agrees to call him Napoleon from now on. The cat—still intent on chasing him and carried back to the city by the currents—reappears once more, recognizing that Napoleon is not a mouse after all but a dog, yet she remains set on pursuing him, a reminder that danger may follow bravery wherever it roams.
