Donají is a fearless Zapotec girl who, even though she's only fifteen, is heralded as a hero by her village. In Codex Black, Donají sets out on an adventure--accompanied by the god that lives inside of her poncho--to find her missing father. Along the way, she meets a 17-year-old winged Mexica warrior named Itzcacalotl, and over time their temporary partnership blooms into an incredible friendship.

The search brings the young pair closer to danger and deeper into mystery than either could have predicted. What exactly was Donají's father involved with? And how did a simple search for a missing relative lead Donají and Itzcacalotl into a fight with a terrifying bat monster to defend an entire village?!