Morrigan Christine Parker finds that turning 18 carries a heavy weight when you're the only daughter of Rhiannon MacCallan, disgraced high priestess to the goddess Epona, in Cast's down-home follow-up to 2006's Divine by Choice. After Rhiannon betrayed Epona, the goddess bestowed her favor on Rhiannon's look-alike, Shannon Parker. Rhiannon promised her allegiance to the evil god Pryderi, but recanted after Morrigan's birth, giving the child over to Epona's protection and the care of Shannon's parents. Now Morrigan comes of age and learns more about her heritage from her adoptive grandparents and the wind-borne whispers of Pryderi and Epona. While visiting the Alabaster Caverns State Park and exploring her power over rocks and crystals, Morrigan is unexpectedly transported to the mystical realm of Partholon, where she must find Shannon and fulfill her destiny.