Ivan introduces himself: he’s a gorilla, and he’s lived at the Big Top Mall and Video Arcade for the last 27 years—fortunately, like all gorillas, Ivan is patient. While the other animals at the mall (like Ivan’s best friend, an elephant named Stella) perform in three shows per day every day of the year, Ivan doesn’t have to. He just has to be himself. However, Ivan isn’t totally sure who he is—the depiction of him on the billboard by the freeway shows Ivan as an angry, dangerous beast. In reality, Ivan is calm and peaceful. He lives in his “domain,” a cage made of glass and concrete so that people can look at him all the time.
Ivan spends his days eating and drawing pictures for the gift shop. In the evenings he listens to Julia, the custodian George’s daughter, talk to him. She’s an artist too, so they understand each other. Ivan also watches TV with Bob, a small stray dog who sleeps on Ivan’s belly every night. Though they mostly watch Westerns, Ivan once saw a gorilla on a nature program—and that’s the only reason he knows he’s not the only gorilla on earth. Stella has also told Ivan that she believes he’ll see a real gorilla again someday, and Ivan believes her because she’s old and wise. She used to work in a circus and only came to the mall after sustaining an injury to her foot. Her foot often bothers her and gets reinfected.
The Big Top Mall is experiencing financial difficulties, since Ivan “isn’t cute anymore.” He’s not attracting as many visitors as he used to. So the owner, Mack, purchases a baby elephant to attract more people to the mall. Stella is incensed by this turn of events. She has to coax the tiny baby out of the truck when she arrives, and she hurts her foot in the process. The baby’s name is Ruby, and Stella explains to Ivan that Ruby was born in the wild but just came to them from a circus. There, trainers chained all of Ruby’s feet to the floor for 23 hours per day to break her spirit.
Ruby proves to be curious and blunt. She tells Ivan that humans killed her parents and is impressed with Ivan’s drawing skills. As Ruby settles in, though, the infection in Stella’s foot gets worse. One evening, Stella is clearly ill and Julia begs George to call Mack for help. Mack insists that if Stella isn’t better in the morning, he’ll call the vet. But that night, after asking Ivan to promise to help Ruby get somewhere where she’ll be able to live a better life than she did, Stella dies. Ivan knows the promise will be impossible to keep.
Ivan does his best to comfort Ruby over the next few days. Since she loves stories, he agrees to tell her his story of his youth. He was born in a rainforest and had a twin sister, Tag. His name was Mud because, even then, he was an artist who drew with mud. Life was perfect—until people came, captured Ivan and Tag, and killed their parents. Tag died in the crate as they got further away from home. Mack adopted Ivan and raised him like a human for several years. It wasn’t until Mack’s wife, Helen, left him that Mack finally brought Ivan to live at the mall. Ivan was thrilled to see his domain—there was nothing to break in it—but he didn’t realize he’d be here for so long.
A few days after Stella dies, Mack decides it’s time to train Ruby to do tricks. He takes her into the ring and walks her in endless circles for hours. Not long after George and Julia arrive for George’s shift, Ruby, exhausted, sits and refuses to move. Mack loses his temper and threatens Ruby with a claw-stick—but Ruby hits Mack in the groin with her trunk. Julia and George return Ruby to her domain and, later, Julia gives Ivan some finger paints.
Ruby has bad dreams and, when she wakes in the night, she asks if she’s going to die in this domain like Stella. Ivan decides to tell her another story. In this one, a baby elephant needs to go to a zoo, “where humans make amends.” The elephant will get there because a friend of hers made a promise. That night, as Ruby and Bob sleep, Ivan remembers the rest of his story—how poachers cut off his mother and father’s hands, feet, and heads.
As Ivan looks at the billboard the next day, he realizes he knows how to help Ruby. He begins to paint every night with Julia’s finger paints and hides his paintings under the pool in his domain. He experiences a setback when Mack finds one painting and takes it to sell in the gift shop, though he also struggles to know exactly what to paint. But then, as Ivan and Bob watch TV, Ivan watches a commercial for the zoo. This shows Ivan the imagery he needs for his giant painting: the zoo enclosures and the zoo’s logo. He continues to paint every night and finally, one night, realizes the last thing his painting needs: the word “home.”
Finally, Ivan is ready to show Julia his work. He shoves his paintings out of the hole in his glass. At first, she doesn’t understand. But when she tries to leave, Ivan beats his chest to get her attention, frightening her. Julia realizes that all of Ivan’s small pieces of painted paper fit together to make one big picture of Ruby at the zoo. She convinces George to help her put Ivan’s massive painting on the billboard.
Though Mack is enraged when he first sees the billboard, he soon is thrilled about the media attention. People come to see Ivan, even reporters. Finally, reporters with a big camera come and take videos of the dirty cages and the claw-stick. After the piece airs on the evening news, protesters begin to gather outside the mall every day, advocating for Ruby and Ivan to be moved to the zoo. After a man with a checklist comes to inspect the mall, Mack seems upset—and days later, a woman from the zoo, Maya, arrives with a Ruby-sized box.
Not long after, more people arrive with more boxes, one of them Ivan-sized. The boxes sit overnight and that night when George arrives, he and Julia say goodbye—but Julia says this is a good thing. Ivan and Ruby get in their boxes the next day, and a drink puts Ivan to sleep.
When Ivan wakes up, he’s in a clean glass cage. After a few days, Maya starts showing him videos on a TV of a gorilla family that doesn’t have a silverback. A few days after that, she pulls aside a curtain on Ivan’s cage—and on the other side is the gorilla family Ivan has been watching on TV. Soon, Ivan is able to leave his cage and join the other gorillas. After a while, Ivan starts to feel like a silverback—and he rediscovers his childhood love of painting with mud. Best of all, one day Maya shows him video of Ruby, happy with the other elephants.
One evening, Julia and George come to the zoo with Bob hidden in Julia’s backpack. Bob now lives with their family to keep Julia’s mom Sara company, and George is going to start a job at the zoo soon. Julia tells Ivan that Ivan did it—he saved Ruby.