Here's the summary of this book which is to be released September 1st:
Everyone has a soul mate. But what do you do when your soul mate would rather give his soul to the demons than be with you?
Seventeen-year-old Erin has a problem. Seth has been hers forever, but now an ancient promise is tearing him away. And Reuel, the demon to whom the promise was made, will stop at nothing to force Seth to forsake Erin and to worship him.
How can Erin win against a pledge so binding that it has damned countless others to the same fate she and Seth will face if Reuel wins – an eternity alone?
The answer lies in the past. To find it, Erin and Seth must risk all, travelling back in time to a dangerous world where love is forbidden, and life – and death – hang on a promise.
Follow Erin and Seth as they travel to ancient Shenaya to break the pledge that has plagued their families for millennia. Caught in a war between the Angelic Guardians and the Gefallen, the disembodied dead, they must fight to keep their souls in tact and their love untainted.