A bank teller discovers he is actually a background player in an open-world video game, and decides to become the hero of his own story. Now, in a world where there are no limits, he is determined to be the guy who saves his world his way before it's too late.

Wreck-It Ralph is the 9-foot-tall, 643-pound villain of an arcade video game named Fix-It Felix Jr., in which the game's titular hero fixes buildings that Ralph destroys. Wanting to prove he can be a good guy and not just a villain, Ralph escapes his game and lands in Hero's Duty, a first-person shooter where he helps the game's hero battle against alien invaders. He later enters Sugar Rush, a kart racing game set on tracks made of candies, cookies and other sweets. There, Ralph meets Vanellope von Schweetz who has learned that her game is faced with a dire threat that could affect the entire arcade, and one that Ralph may have inadvertently started.