Merlin's Dragon

Long ago, at the dawn of Merlin's world, a strange little creature appeared. Part lizard, part bat, his eyes glowed with mysterious light. Meet Basil -- someone very small in size but very large in destiny.

When Basil discovers a terrible new threat to his world and the great wizard Merlin, he begins an epic journey that takes him from the Great Tree of Avalon to the outermost edge of the spirit realm. But his boldest journey by far will be to face his own deepest fears. Only if he survives will he be able to save Merlin -- and find a future as great as his heart.

This is #6 in The Lost Years Of Merlin Series.