Shifter's Shadow by Ella Summers — book slip

Tested by the gods, Leda and her angelic mate Nero venture into the City of Ashes, a fallen fortress in the Western Wilderness where nightmarish monsters reign supreme and an ancient secret is buried.

To survive the Gods' Trials, they will have to save the city—and they will have to do it without their magic. Their victory, however, comes at a heavy price.

And the secret they uncover will upset the balance of power between Earth and heaven.

Fifth in the Legion of Angels series.