Set after the events of Continental Drift, Scrat's epic pursuit of his elusive acorn catapults him outside of Earth, where he accidentally sets off a series of cosmic events that transform and threaten the planet. To save themselves from peril, Manny, Sid, Diego, and the rest of the herd leave their home and embark on a quest full of thrills and spills, highs and lows, laughter and adventure while traveling to exotic new lands and locations.

A series of interconnected short films are the backdrop for a maniac screenwriter who pitches insane storylines featuring some of Hollywood's biggest and brightest.

Times are changing for Manny the moody mammoth, Sid the motor mouthed sloth and Diego the crafty saber-toothed tiger. Life heats up for our heroes when they meet some new and none-too-friendly neighbors – the mighty dinosaurs.