Follows Ember and Wade, in a city where fire-, water-, land- and air-residents live together.

Babies both human and beast are created up in the stratosphere, by the clouds themselves. One cloud specializes in "dangerous" babies, creating a challenge for his loyal stork that has to deliver them.

In a world where dinosaurs and humans live side-by-side, an Apatosaurus named Arlo makes an unlikely human friend.