Ed is at his happiest when winter comes and Green turns to White. White means snow and playing on his fast, sleek, shiny sled.

But one day, some other sleds whizz by – faster, sleeker, shinier – making Ed's sled seem old and dull and slow.

There is only one thing to do… Ed must build a new sled, so spectacular, it will stop everyone in their tracks.

But while he is busy working, competing to be the best, things around Ed are changing. White is disappearing and Green is returning…