As the son of a Viking leader on the cusp of manhood, shy Hiccup Horrendous Haddock III faces a rite of passage: he must kill a dragon to prove his warrior mettle. But after downing a feared dragon, he realizes that he no longer wants to destroy it, and instead befriends the beast – which he names Toothless – much to the chagrin of his warrior father.

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.

Inventor Flint Lockwood creates a machine that makes clouds rain food, enabling the down-and-out citizens of Chewandswallow to feed themselves. But when the falling food reaches gargantuan proportions, Flint must scramble to avert disaster. Can he regain control of the machine and put an end to the wild weather before the town is destroyed?