D. A. 
Darkisle: The Final Battle 

3rd book in the Dark Isle trilogy. Dark Isle (book 1) won Scottish Children’s Book Award. All seems well in Marnoch Mor. Bertie the dodo, Aldiss the rat and Shona the dragon are looking forward to Christmas. However, Morag is having bad dreams — an old enemy is trying to reach her. And when another former foe turns up on her doorstep it is clear something is badly wrong. Morag and her friends are soon forced to face a powerful new threat. The battle for the Dark Isle of Murst must be won…or Marnoch Mor will be lost.