Odd and the Frost Giants

The winter isn't ending. Nobody knows why.
And Odd has run away from home, even though he can barely walk and has to use a crutch.
Out in the forest he encounters a bear, a fox, and an eagle - three creatures with a strange story to tell.
Now Odd is faced with a stranger journey than he had ever imagined.
A journey to save Asgard, City of the Norse Gods, from the Frost Giants who have invaded it.
It's going to take a very special kind of boy to defeat the most dangerous of all the Frost Giants and rescue the mighty Gods. Someone cheerful and infuriating and clever.
Someone just like Odd...