Turner: Deep Change

Juri Turner, the human-born dragon and the dragons of Mur continue to aid in the fight against aliens that invaded Earth twenty-three years ago. Now, more trouble has arisen.
With a fleet of enemy battleships heading for a base in the Alpha Centauri star system, to further muddle matters, a homegrown problem is discovered: a plot to take over Earth's government by a self-styled sorcerer.
Then, an enemy base is discovered in another star system but as preparations are made to go and blow it to kingdom come, captive humans are detected. Will the plan to use Juri and her ability to open portals to help effect a rescue work? And if it does, will it work when more captives are found?
And, when at last the location of the enemy's home planet is discovered, and plans are made to fight them on their turf, will it be met with success considering that they vastly outnumber Earth and their allies? Or will this become a never-ending war?
The survival of Earth and even the welfare of other species in the galaxy hinge on the answer.