Outside the Jingling Bros. Circus, a playful nod to the Ringling Bros. spectacle, a hospital ward clerk drags out a lion in a wheelchair who has clearly had a nervous breakdown. Watching this scene, Mouse expresses his disappointment at the lion’s condition and then guides us into a long flashback that explains how things spiraled to this moment.
In the retelling, the lion stands as the undisputed king of beasts, and fear grips every other animal. When he roars, the jungle parts in alarm and the crowd of creatures scatters. A gorilla, in particular, shrieks, grows smaller in a panic, and bolts away.
Then the lion meets a tiny mouse who says Boo, and the moment shifts the balance of power in a surprising way.
> "Boo,"
That single word sends the lion into a startled double take, makes him tremble, and drives him to climb up a tree in a rare moment of vulnerability. He eventually comes down, raises his head, and roars at the audacious tiny intruder. But the mouse proves to be far tougher than expected. The chase ends abruptly when the mouse, walking away, accidentally steps straight into the lion’s mouth.
The lion catches the mouse and aims to swallow him, hoping to end the threat once and for all. Yet his attention is broken by another problem: a tooth has fallen out during the scuffle. The mouse hides in the gums between the teeth, and by the time the lion notices the missing tooth, it’s already too late. The mouse slips out of the mouth and even rolls the lion’s tongue like a window shade, while the lion, frustrated, grabs the mouse with his tongue and tries to pull him back in for a fatal swallow.
Inside the lion’s stomach, the mouse finds two bones and uses the lion’s ribs as a playful xylophone, turning a moment of menace into a strange, musical misadventure. The lion escalates in a desperate bid to kill the mouse by lighting a bomb with a match, placing it in his own mouth, and swallowing it. The mouse spots the danger inside and screams, escaping again as the bomb detonates. The explosion wounds the lion only slightly, but a new annoyance follows: the mouse bites the lion’s tail, gnawing with determined glee.
The mouse then tunnels into the lion’s head and pulls out firecrackers, which go off in a noisy display. He even cooks the lion’s tail, provoking a fresh roar of pain. The lion hurries to a lake to cool himself down, while the mouse continues to torment him by pulling out a safety pin and giving a sharp poke to the rear.
The harassment doesn’t stop there. The mouse annihilates the lion’s nerves by attacking his feet, blowing a toot in his ears, biting his nose, and finally kicking him out of a hut, leaving him a nervous wreck who pounds through the jungle in a frantic, unsteady scramble.
Returning to the present, the mouse wonders how anyone could be afraid of a mouse, and then another mouse appears and says Boo. Despite being a mouse himself, the second creature intones, “A mouse,” and in a moment of fear mirroring the lion’s own past, he screams and darts off into the undergrowth. The echo of the lion’s earlier panic lingers as the story closes, leaving the viewer with a peculiar reminder of how fear can invert expectations and loyalty can come from the most unlikely of adversaries.
