After being stolen from the zoo and waking up in a circus, a lion learns the existence of animal cruelty, so he and animal friends must work together to shut down the circus down for good.
The film opens at the Bronx Zoo where Leo the lion lives. He is a self-centered lion who lives by himself in his enclosure and thinks that he's the most important part of the zoo. People would go to his enclosure and see him do all sorts of tricks. One night, while Leo was asleep, a man snuck into his enclosure, shoots him with a tranquilizer dart, and drags him away.
The next day, Leo wakes up in a circus cage, and the man who lion-napped him is a ringmaster. He was amused by his tricks and when he asks the zoo owner to buy him, he disagreed. So he stole him. Leo meets the circus animal performers, a tiger named Vlad, a grizzly bear named Billy, a chimp and Sebastian, a giraffe named, George, and two elephants named Seymour and Linda. During rehearsal, Leo looks around and see's how cruel the animals are being treated by the humans and he confronts a lion tamer. When she whipped Leo, he angrily attempted to kill her until the ringmaster tranquilizes him and drags him back into his cage and chains him up. Sebastian then free's the now horrified Leo and shows him why he was sent here.
Sebastian introduces Leo to Savannah, a lioness who rots in her cage all chained up, due to screwing up rehearsal and her performances. As a result, the ringmaster locked her in the cage, and replaces her with Leo because of his amusing talent. So Leo brings all the animals, including Savannah, together to come up with a plan to exposed the animal cruelty to the audience and shut down the circus for good. Leo fools around with the tamer which causes the audience to boo at them and he tells Sebastian to open the backstage curtain, revealing the animals being abused the humans, shocking the audience, and they demanded their money back. When the ringmaster tried to lie to audience, the police came and arrested him.
The next day, the circus was shut down and Leo, along with the rest of the animals were shipped to the Bronx Zoo where they lived happy and free. Leo got his fans back, but the one thing he loves the most, is Savannah, who now lives with him in his enclosure. THE END!
Chris Pratt as Leo, a talented zoo lion who was stolen and taken to the circus to replace Savannah.
Kevin Michael Richardson as Vlad, a tiger who jumps through hopes and dreams off being free.
Scarlett Johansson as Savannah, as lioness who rots in a cage for screwing up her performances.
John Goodman as Billy, a southern grizzly bear who's plays the banjo.
Hugh Laurie as Sebastian, an intelligent chimp who rides a unicycle across a tight rope.
Matthew Broderick as George, a giraffe who twirls hula hoops with his neck.
Brad Garrett as Seymour, a male elephant who balances on a ball.
Melissa McCarthy as Linda, a female elephant who balances on a ball.
Andy Daly as The Ringleader, the main antagonist of the film. He's a greedy businessman who abuses his animal performers and attempts to make more money.