Everyone knew that, while magic was fine, demons were evil. So evil that humans had gone to war a hundred years before and destroyed them all.

All except for the last few demons—chained and emasculated— used for their power by government. The weather sorceress, Beth Parker, knew nearly all of that was a lie.

She was part of the movement to get those poor bastards free when the enslaved demons literally sacrificed themselves to save the world from an alien attack.
But the aliens are still out there. With a killer beam that can sterilize the earth. And an armada in case that falls through.

And the only chance for the Earth to survive are those very demons the Earth tried to destroy.

Now, she just has to convince the demons....