In the videogame universe, Ralph (John C. Reilly) is what's known as a bad guy. While the hero of his game - Fix-It Felix Jr (Jack McBrayer) - laps up the adulation of the pixelated community, block-busting Ralph is a virtual outcast - and he's sick of it.
In pursuit of a medal to prove he's capable of matching his goodie-two-shoes rival, Ralph exits his own world and crash lands in candy-coated racing game Sugar Rush, where he meets sparky pre-teen Vanellope von Schweetz (Sarah Silverman).
Vanellope is also ostracised by her peers for being a 'glitch', a mistake in the game that could cause it to crash beyond repair. But recognising a fellow outsider, Ralph decides to help Vanellope achieve her dream of participating in the karting championships, even though it could spell 'game over' for both of them.