Animal pals Alex, Marty, Melman, and Gloria are still trying to make it back to New York's Central Park Zoo. They are forced to take a detour to Europe to find the penguins and chimps who broke the bank at a Monte Carlo casino. When French animal-control officer Capitaine Chantel DuBois picks up their scent, Alex and company are forced to hide out in a traveling circus.

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.

On a high mountain plain lives a lamb with wool of such remarkable sheen that he breaks into high-steppin' dance. But there comes a day when he loses his lustrous coat and, along with it, his pride. It takes a wise jackalope - a horn-adorned rabbit - to teach the moping lamb that wooly or not, it's what's inside that'll help him rebound from life's troubles.

One by one, a flock of small birds perches on a telephone wire. Sitting close together has problems enough, and then comes along a large dopey bird that tries to join them. The birds of a feather can't help but make fun of him - and their clique mentality proves embarrassing in the end.

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.