Max (Max Records) is a lonely boy with an active imagination. His older sister, Claire (Pepita Emmerichs) does nothing when her friends crush Max's snow fort (with him inside) during a snowball fight. Out of frustration Max messes up her bedroom, specifically destroying a special card that Max had made for her. His mother, Connie (Catherine Keener) invites her boyfriend (Mark Ruffalo) to dinner. Max wears his wolf costume, acts like an animal and demands to be fed, and when his mother gets upset, Max throws a tantrum and bites her. She yells at him and he runs away. Max finds a small boat in a pond, which he gets into and departs.



Sailing across the ocean, Max eventually reaches an island. Still in wolf costume, he explores the island and stumbles upon a group of six large creatures. One of them, Carol, is in the middle of a destructive tantrum while the others attempt to stop him. As Carol wreaks havoc Max tries to join in on the mayhem but soon finds himself facing the suspicious anger of the wild things. When they contemplate eating him, Max convinces them with a lie that he is a great king with magical powers capable of bringing harmony to the distraught group. They promptly crown him as their new king and introduce themselves:



* Carol (voiced by James Gandolfini), the most impulsive and charismatic of the wild things.

* Ira and Judith (voiced by Forest Whitaker and Catherine O'Hara), a gentle-speaking pushover and his aggressive, "downer" girlfriend.

* Alexander (voiced by Paul Dano), a goat-like wild thing who is constantly ignored, belittled, and mistreated.

* Douglas (voiced by Chris Cooper), a bird-like peace-keeper who is Carol's best friend.

* The Bull (voiced by Michael Berry Jr.), a quiet and intimidating beast who mostly keeps to himself.

* K.W. (voiced by Lauren Ambrose), the loner of the group whose constant departures irritate Carol greatly as he wants all of them to stay together.



Soon after Max arrives, K.W. returns and Max declares a "wild rumpus", in which the wild things smash trees and tackle each other, ending with them all piling on one another then going to sleep, with Max at the center of the pile. Carol takes Max on a tour of the island, showing him an intricate model Carol built out of sticks, depicting what he wishes the island looked like. Inspired by this, Max orders the construction of an enormous and fantastical fort, with Carol in charge of the construction. As Max bonds with Carol, K.W. brings her owl friends Bob and Terry to the nearly completed fort. Disagreement ensues again, as Carol feels the togetherness of their group is threatened by these outsiders. To release their frustrations, Max has the tribe divide into "good guys" and "bad guys" for a dirt-clod fight, but Alexander is hurt during the game. Tension mounts between the wild things as it becomes increasingly obvious Max favors some of the wild things over others.



Eventually, Max finds Alexander alone in the fort that they built and has a conversation with the wild thing, who is still hurt from the dirt-clod fight. Alexander reveals that he always suspected that Max is "regular, like us," not a king with magical powers, but warns Max to never let Carol know, though quickly Max's secret is exposed when Carol throws another tantrum and Douglas tries to make Carol accept the fact that Max is not and never was a king. Carol becomes enraged and accidentally rips Douglas' arm off, though only sand pours out of the wound. Carol then chases Max into the forest and threatens to eat him. Max is saved by K.W., who hides him in her stomach. Max listens as K.W. explains to Carol that their lives are already difficult, with Carol's out-of-control tantrums only making things worse. Hearing this, Max decides to leave the island.



Max seeks Carol out but only finds the crushed remains of his model island. Max leaves a token of affection for him to find. The other wild things escort Max to his boat and he sets off for home. Carol, after finding Max's token and regretting his rage, arrives just in time but is unable to speak, so they howl to one another. Max returns home, apparently just a short time after he left. He is embraced by his distraught mother, who gives him a piece of cake and sits with him as he happily eats it.