The Sunken Tower — James E. Wisher

For generations the Dragonriders protected Dragonspire Village Now Yaz has to rescue them. He only hopes that they know where his father was taken. Meanwhile, the Dark Sages have finally captured Ariel. With her in their grasp, they set out to seize the final Dragonspire. Only a mad cult stands between them and fulfilling their mad ambitions. Can Yaz free the Dragonriders and find his father before it's too late?