Four orphans each receive a Golden Ticket, each via a different film "parody" - Lucy (The Da Vinci Code), Edward (Nacho Libre), Susan (Snakes on a Plane) and Peter (X-Men trilogy). This ticket entitles them to visit the Willy Wonka Chocolate Factory (Charlie and the Chocolate Factory). Willy tells the kids that the secret ingredient in his chocolate is human parts, and he plans to keep the orphans in his factory to use them for his chocolate. He succeeds in getting the ingredients, which includes Lucy's sweet "heart", Edward's "peanuts", Peter's "surprise" tooth and Susan's lemon "head" to the tune of 'Fergalicious'. He then brands Peter's backside and locks the orphans in an old room, where they bemoan the lunacy of their captor. Soon, they hear Willy looking for them, and all rush to find a place to hide. Lucy runs to a room with a wardrobe (The Chronicles of Narnia: The Lion, the Witch and the Wardrobe) and after a series of items fall on her, including a live woman, she climbs inside to find a snowy forest. When her tongue gets stuck to a pole (A Christmas Story), half-man half-goat Mr. Tumnus arrives to help her.
He welcomes Lucy to "Gnarnia" by showing her around his home (as a "parody" of Cribs) and introducing her to a rapping Kanye West-lookalike brother and several goat-women. When Lucy expresses gratitude to his friendship, he gives her a spy-secured camera, which painfully scans her retina before playing a film that warned her of the grave danger she is in (Mission Impossible III). Back at the Chocolate Factory, Edward follows Lucy through the closet to Gnarnia and is nearly hit by a fast sleigh with a license plate (Tokyo Drift). Onboard is the White Bitch, whom Edward calls "Stifler's Mom..." (American Pie series). She convinces him to trap the other orphans. Eventually everyone makes his or her way to Mr. Tumnus' house, where the orphans discover a clue in a painting of the Last Supper that lead them to learning that they are all related to one another, and that the White Bitch killed their parents. Edward goes to see the White Bitch at her castle and realizes all she cares about are the other orphans. After having his feelings dismissed and realizing he got the wrong tattoo on his back (Get Rich or Die Trying), he realizes that she is evil and refuses to tell her where the other orphans are. Unfortunately, the White Bitch flashes him her chest and a transfixed Edward gives her the information unhesitatingly. A group of cameramen and an Ashton Kutcher-lookalike then appears (Punk'd) to mock him, and Edward is locked in the castle prison.
A talking beaver named Harry sends Lucy, Susan, and Peter out of the winter scenery and into the woods to train for the war. They end up in a castle where they meet three adults dressed as students (named after the characters of Harry Potter), who help the orphans train for the war. Back at the White Bitch's castle, as she prepares a WMD that will create a new continent for her and her followers to live on (Superman Returns), her assistant hands her a computer with her MySpace on the screen with an IM from Silas saying that the kids have escaped. Edward tries to find ways to break out of prison, and does so with the help of Captain Jack Swallows (Pirates of the Carribean). Swallows brings Edward to his ship named Fantasia (after American Idol), where rapping male and girl-band female pirates tell Edward about the life of a pirate. However, it was a trap to deceive Edward, as Swallows sell him to the White Bitch and reveals that the ship they are on is an amusement park ride. With Edward secured, the White Bitch kills Jack Swallows. Edwards grabs the WMD from her but accidentally drops it into the water, triggering the first stages of an earthquake.
Upon finishing their training, Lucy, Susan, and Peter, head to the camp of Aslo. There they encounter James Bond and his girls (specifically Casino Royale), Chewbacca, Borat, Lord of the Rings characters, Robin Hood, and Peter's X-Men classmates. All of them promise to help them fight the White Bitch and save their brother. Aslo agrees to help the orphans on the condition that he may seduce them, including Peter. Afterwards they arrive to the castle, where Aslo and Silas fight briefly and pull each other's hair (Enter the Dragon) before Aslo emerges victorious. Edward is rescued, but after encountering the White Bitch Aslo is quickly killed off. When the orphans learn this, they promise to fight tomorrow, but until then to party. As the resistance sang and danced, Peter gets a night with Mystique but reveals disturbing fetishes, while Susan drinks and ends up vomiting on the resistance army. As a result, no one shows up to support the foursome when they face the White Bitch's army.
As promised, Jack Swallows arrives to attempt revenge against the White Bitch. Somehow, her face changes to that of Davey Jones and she play Miss New Booty on a turntable. This was revealled to be an octopus stuck on her face, and she throws it to Swallows', who loses sense of direction and ends up retreating. Back to the battle at hand, the foursome charges against the White Bitch's army, which include Star Wars stormtroopers. All the children are struck down, and the White Bitch steps forward to kill Peter, who is the last one standing. He grabs a remote off the ground, which he uses to pause time (Click). After experimenting it on passing joggers, he heals the injuries of his comrades, and the orphans proceed to kill the army as it is "paused" to remain in the same position. When the army is destroyed, the ground starts shaking again, and Edward uses the remote's TiVo menu to erase the White Bitch's evil plot.
Before they can kill the White Bitch, Peter stops them and makes a speech about how they will give her a fair trial, yet before the lecture is over Jack Swallows runs the White Bitch over with his cartwheel. Harry Beaver promotes all four of them Kings and Queens of Gnarnia. They are each described: Peter "the heroic", Edward "the loyal", Susan "the just", and, Lucy, the "dumb-shit". They rule Gnarnia for many years, and in their old age, they discover the wardrobe once again and walked through it, becoming young again. Borat appears to congratulate them, but Jack Swallows' cartwheel runs them over, and then he says "NOT!". Then he turns around and smacks his own behind and then the credits roll. In the Unrated, Longer Version of the movie, instead of Borat, Willy Wonka comes in and says "I told you it was going to be an epic adventure" instead. The Oompa-Loompas come in and start singing the Willy Wonka theme song as he puts a 'do not disturb' sign refering to the girl in the wardrobe. Then, Jack Swallows comes in with the wheel and crushes the Oompa-Loompas and the orphans/rulers of Gnarnia.