Raised as a normal girl in Oklahoma for the first eighteen years of her life, Morrigan discovers her true heritage as the only daughter of Rhiannon MacCallan, disgraced high priestess to the goddess Epona, which leads her back to the world of Partholon. Expecting to be welcomed back with open arms, instead she is shunned and, desperate to belong, confronts forces she doesn't fully understand and cant' control.