Earth and Water and their guides Erde and N'doch have survived Fire's fury and they've found allies, new and unexpected. Even better, they've found Air's guide, but unless they find the Dragon Air herself, their quest will fail and the World's destruction is assured.
Erde, N'doch, and Paia search with their dragons to find the last - Air. Without Air, the mission will never survive. Paia's job is difficult, but Air's dragon guide's job seems impossible. This last book is a great read, but ended differently than I expected, leaving me a bit disappointed.