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. When Scrat's acorn sends an asteroid to Earth, the Herd must find a way to stop the asteroid from hitting Earth with the help of a returning friend.