Trama

When Litwak's (Ed O'Neill) Family Fun Center & Arcade closes at night, the various video-game characters leave their normal in-game roles and are free to travel to other games. Within the game Fix-It Felix, Jr. (Jack McBrayer), the characters celebrate its titular hero but loathe the game's villain character, Wreck-It Ralph (John C. Reilly). Ralph is a gigantic 9 feet tall, 643 pounds, but a man with a soft heart who is the villain of the arcade game Fix-It Felix Jr. Problem is, nobody loves a Bad Guy.

In the game, Ralph is perched on the top of an apartment building called Niceland, from where he wreaks havoc, while Felix tries to fix the destruction wrought by Ralph. Felix has a magic hammer to help him in his quest. When Felix fixes an apartment, he gets a medal, but there are no medals for Ralph. At the end of the day, Felix gets to go home, while Ralph's home is an actual garbage dump.

At a support group for video-game antagonists, Ralph reveals his desire to stop being the bad guy. Ralph explains that after 30 years of doing the same thing and getting no respect for his job, he feels that he doesn't want to be the bad guy anymore. The other members claim that he can't mess with the program of his game, and soon finish the meeting, leaving Ralph still dejected.

Going through 'Game Central Station' (a power strip with surge protectors that has all the arcade's game plugged into it), Ralph returns to his game. If a character dies outside of their own gaming console, they can never regenerate.

Ralph finds the other characters celebrating their game's 30th anniversary without inviting him. Felix reluctantly invites Ralph to join them. Ralph gets angry at the cake in which all characters have their figurines on top of the building, but Ralph's figurine is left at the bottom, in chocolate flavored mud. The others ostracize Ralph, saying he would have to earn a medal to be able to join them, just as Felix does in their game. Ralph destroys the cake in a fit of rage and angrily leaves, intending to somehow get a medal of his own, and prove he can be a hero.

Going off to a bar-game called Tapper's, Ralph is unsure what to do, when he encounters a soldier from a new first-person shooter named "Hero's Duty." At Tapper's, Ralph learns he can win a medal in the first-person shooter game Hero's Duty. On his way there, Q*Bert a homeless character whose game has been unplugged, is at the station and Ralph tells him where he is going, then is off.

Ralph enters the game and encounters Sergeant Tamora Jean Calhoun (Jane Lynch), its no-nonsense leader. Between game sessions, Ralph accidentally gets the first-person shooter (aka a kid playing the game inside the arcade) killed, and the game ends. As it does, a giant beam of light shoots out of the top of a nearby tower, attracting the Cy-bugs, and incinerating them as they are drawn into its light.

As the game begins to reset for the next player, Ralph learns that the medal he wants is at the top of that tower. Removing his armor, he climbs the tower and finds himself in a room full of Cy-bug eggs. Making his way through them all, he finds the medal. Ralph gets a bit too excited, and accidentally steps on an egg, releasing a Cy-bug newborn.

The Cy-Bug clings to Ralph as he stumbles into an escape pod that launches him out of the game. The pod escapes into the portal to 'Game Central Station.' It bounces around the station, before sending Ralph into a nearby racing game called 'Sugar Rush.' Crash-landing, the ejector seat sends Ralph in one direction, and the Cy-bug in another, sending it into a deep pit.

Meanwhile, with Ralph missing, a girl reports to Litwak, the arcade owner that Fix-It Felix, Jr. is malfunctioning. Since broken games get unplugged, leaving their characters homeless, Felix goes to find Ralph. Felix finds Q*Bert who tells Felix that Ralph has gone to Hero's Duty for the medal.

Ralph crash-lands in Sugar Rush, a kart-racing game. As he searches for his medal, he meets Vanellope Von Schweetz (Sarah Silverman), a glitch prone character who takes the medal and uses it to buy entry into a race. The race will determine the new racing roster, as the first 9 racers will represent SugarRush as the next day's racers. The event is pay to play, and the fee to compete is one gold coin from previous winnings. King Candy (Alan Tudyk) the competitive and stubborn ruler of Sugar Rush, and the other racers refuse to let Vanellope participate, claiming she is not really part of the game. Ralph arrives at the start line and demands his medal back, but Vanellope manages to escape him.

Ralph is then captured and brought before King Candy. The King is at first shocked that Ralph appears to be 'game-jumping,' but Ralph claims that all he wants is his medal back. Candy realizes that Vanellope used Ralph's medal to buy her way into the race. However, the King informs him that since it's now been entered into the game's programming, the only way he can get it back is if he or someone he knows wins the race (and returns the medal to him) & asks him to leave Sugar Rush.

Ralph escapes King Candy & stumbles upon Vanellope, who is being bullied by the other racers, who break her car and warn her against entering the race. Ralph intervenes and saves Vanellope. The deal is that Vanellope will return the medal to Ralph once she wins the race. Ralph helps Vanellope build a kart. Ralph and Vanellope break into a cart-baking factory, and Ralph helps Vanellope as best as he can. However, his attempts to help make the car look like a bakery-fueled mess, but Vanellope loves it anyway, and has Ralph sign his name on the side in icing. However, their intrusion is soon found out, and King Candy and his police force soon arrive. Ralph asks Vanellope to drive away, but she reveals that she doesn't know how to drive a real kart.

Ralph then uses his giant hands to help propel them away from the pursuing King and his police force, losing them when Vanellope directs him to a secret entrance near Diet Cola Mountain. At her home in Diet Cola Mountain, an unfinished bonus racing course, Ralph builds a new track for Vanellope and discovers that she is a natural racer. When Vanellope glitches, she can suddenly move from one location to another. Inside, Ralph finds a giant lava pit over which Mentos stalactites hang overhead. When one drops into the soda, it causes a heated geyser to erupt.

Back in Hero's Duty, Felix meets Calhoun, who warns that the Cy-Bugs are capable of taking over & destroying any game they enter. Calhoun tracks the Cy-Bug, as Cy-Bugs behave as a virus once outside their game. Cy-Bugs only know how to eat, kill and multiply. Calhoun is greatly concerned, because Cy-bugs can multiply when plenty of food is available, and with the candies and sweets of 'Sugar Rush', the possibility of the game being overrun by them is highly possible. Calhoun warns that once the Cy-Bugs destroy SugarRush, they will go after every other game in the arcade, until everything is destroyed. Calhoun wants to find the Cy-Bug before it lays its eggs.

Felix worries Ralph will meet the same fate as Turbo, the protagonist of the racing game TurboTime, who grew envious of a new RoadBlasters cabinet's success and invaded it, resulting in both games being unplugged.

Meanwhile, Felix and Calhoun arrive in SugarRush and have discovered the crashed escape pod, but no sign of Ralph or the Cy-bug. Calhoun attempts to use a detector for finding the bug, but it can't focus because of the sugar particles interfering with the detector. Here they fall into "Nesquik-sand", work together to escape, and begin to fall in love. As the pair searches for Ralph and the Cy-Bug in Sugar Rush, they separate when Felix, enamored with Calhoun, inadvertently reminds her of her fiance, who had been killed by a Cy-Bug in her backstory on her wedding day. Felix is imprisoned by King Candy's assistant, Sour Bill (Rich Moore), while Calhoun discovers that the Cy-Bug has multiplied exponentially.

As they prepare to take off for the big race, Vanellope rushes back into the mountain to get something. It is then that King Candy shows up. Desperate, King Candy hacks the game's code to retrieve Ralph's medal and offers it to Ralph (seeking him out at diet cola mountain when Vanellope is busy elsewhere), explaining that letting Vanellope race would be disastrous for both her and the game. Candy thinks that if Venelope wins the race, she will be on game's roster as an avatar to be chosen & if she is chosen, she will be her glitch prone self, thus forcing players to think that the game is out of order & potentially being unplugged.

Fearing for Vanellope's safety, Ralph wrecks the kart. Heart-broken that he has ruined her chance, she claims he 'really is a bad guy,' and rushes back to her hide-out. Ralph returns to his own game, but finds that everyone has evacuated, expecting the game to be unplugged in the morning. Ralph then notices Vanellope's image on the Sugar Rush cabinet and realizes she is an intended part of the game, not a glitch.

Ralph then returns to 'Sugar Rush' and heads for diet cola mountain, finding the King's Sour Bill cleaning up the remnants of Vanellope's cart. Ralph then gets the little Sour Bill to tell that King Candy changed around Vanellope's code, but as to why he did this, the Sour Bill has no clue. Ralph finds that at some point King Candy tried to delete Vanellope's code & locked up everyone's memories, so they can't remember why. And if she finishes the race, the code of the game will reset, and Vanellope will become a real part of the game & not a glitch.

Sour Bill also tells Ralph that both Felix and Vanellope are being held in the King's dungeon, and Ralph sets out there along with the garbage can containing the broken pieces of Vanellope's kart. Ralph finds Felix and Vanellope in King Candy's dungeon and asks Felix to fix the wrecked kart. Using Felix's magical hammer, they repair Vanellope's cart, and manage to free her, with Ralph first admitting what a moron he was. As the race proceeds, the hatched Cy-Bugs attack and Felix, Calhoun, and Ralph battle them.

With the game too overrun with the creatures, they'll need to kill the game to end them. Realizing that it'll mean the end for Vanellope, Ralph stays by the finish line as long as he can, figuring if Vanellope can at least cross the finish line, she'll be able to escape.

Unaware of the Cy-Bugs, King Candy attempts to ram Vanellope off the track, causing them both to glitch. The glitching unmasks King Candy as Turbo, who secretly took over Sugar Rush after surviving the unplugging of TurboTime. Vanellope escapes from Turbo, who is consumed by a Cy-Bug. The group flees the doomed game, but Vanellope finds she cannot pass through the exit. Calhoun says the game cannot be saved without a beacon to attract and kill the Cy-Bugs.

Ralph heads to Diet Cola Mountain, where he plans on collapsing its Mentos stalactites into the cola at the bottom, causing a blinding eruption that would attract the bugs. Before he can finish, Turbo, merged with the Cy-Bug that had consumed him, carries him away.

The newly-powered-up tyrant knocks Ralph around a bit, saying he is the most powerful virus in the arcade and will attempt to take over all the other games for revenge, Ralph battles Turbo, but Turbo dislikes being stopped and quickly overpowers Ralph, flying him above the mountain and sarcastically forcing him to watch Cy-Bugs close in on Vanellope.

Ralph breaks free and dives toward the mountain, intending to sacrifice himself to start the eruption on impact. Vanellope in turn uses her glitching abilities to save Ralph. The eruption starts and draws the Cy-Bugs to their destruction, including Turbo. Because video game characters who die outside their own game are unable to regenerate ever, this means that the Cy-Bugs gets destroyed and Turbo gets destroyed permanently to his death, as the eruption stops Turbo's revenge, because which causes King Candy's code to be destroyed forever.

Vanellope crosses the finish line, restoring her (and the other residents of Sugar Rush's) memory and status as Princess Vanellope, the game's ruler and lead character, while keeping her advantageous glitching ability.

Felix and Ralph return to their game in time for Litwak to see that it still works, sparing it from being unplugged. Calhoun and Felix marry, and the characters of Fix-It Felix, Jr. gain a new respect for Ralph. Ralph also claims that even though he still gets pitched off the top of the apartment building in his game, he loves the view through the glass of the video game box, and seeing his friend Vanellope doing what she loves, he feels great.