Ivan, a silverback western lowland gorilla, lives in the enclosure at Big Top Mall. He performs for Mack, the owner, alongside other performers; a wise and nurturing African elephant named Stella, a spoiled poodle named Snickers, a spunky chicken named Henrietta, a fire truck-riding rabbit named Murphy, a paranoid sea lion named Frankie and a loquacious parrot named Thelma. Ivan is accompanied by a stray mutt, who they later name Bob, who secretly lives in his enclosure. Mack’s janitorial employee George brings his daughter Julia who frequently interacts with Ivan. One day, Julia leaves her old crayons with Ivan who suddenly begins taking an interest in drawing with them. Julia is apparently the only one who can decipher his drawings and what they mean.
The Big Top Mall begins losing business, much to Mack’s concern, but becomes excited when he purchases a baby elephant named Ruby who begins to draw in a crowd. Ivan is initially hesitant over accepting Ruby, especially when she begins to pry into his personal life. When Stella, who has been caring for Ruby, suddenly becomes weaker and unable to perform, Ivan gives Ruby encouragement to embrace the crowd on her own. Afterwards, Ruby asks Ivan to tell her a story and Ivan reveals how Mack and his wife Helen adopted him when he was just a baby. As Ivan got bigger, Mack became forgiving of his animalistic behavior, but Helen left him out of frustration. Mack eventually purchased the mall and turned it into a circus. Stella asks Ivan to look after Ruby and make sure she is free before passing away.
Mack begins to train Ruby for the circus, which displeases Ivan and he decides to find a way to free her. Ivan’s drawings are discovered by Mack and decides to make it the next big act, but despite the publicity in the news, Ivan refuses to cooperate. At night, Ivan and Bob trick the security guard Castello and free themselves and Ruby. At Ruby’s urging, Henrietta, Murphy, Frankie and Thelma are also released and the animals flee the Big Top Mall to escape to the forest on the other side of the highway. To their disappointment, the “forest” is just an intersection and they are surrounded by more city. Alerted by Castello, Mack manages to bring the animals back and tries to keep their escape a secret.
Ruby asks Ivan to tell her another story. At Bob’s urging, Ivan finally explains how he used to live in the jungle with other gorillas. Ivan, then known as Mud, loved to make drawings in the mud and play with his sister Tag who loved playing tag. Ivan was separated by his family when poachers came and he had not seen any other gorillas since.
As George is informed by Mack to keep this incident from reaching the press while mentioning that he fired Castello, Julia sympathetically gives Ivan some finger paints and, inspired, he decides to paint a mural.
The next day, visitors come in along with the reporter Candace Taylor who has heard about the possible escape and decide to film the show. Ivan’s mural, a recreation of a forest and lake, is seen by the crowd who responds positively to it. Julia believes that Ivan wants to be free and informs Candace.
Soon, protesters arrive demanding the release of the animals. Mack finally gives in and decides to shut down the mall. As all the animals are taken away, Mack has one final moment with Ivan, thanking him for his time. Ivan is taken to a big gorilla enclosure at the Zoo Atlantic by Dr. Maya Wilson where he is reunited with his kind. To his astonishment, it is situated right next to the elephant enclosure where Ruby is with her kind. Ivan assures Stella’s spirit that Ruby is safe under his watch.
During the credits, photos and footage of the real Ivan is shown along with a summary of his life. In a mid-credits scene, Ivan is greeted by Bob who has been adopted by Julia and George who come visit the enclosure along with Mack to check in on Ivan.