The Warrior of Aalayfa: Book Three (The Aalayfa Series, #3)

Anatat and the sorceress have resurrected the Old Serpent Woman, but after living among hostile tribes, they are torn apart by political and territorial changes beyond their control. When they are kidnapped by Kilaron, Anatat's estranged son from a parallel world, they have no choice but to stay with him in the desert where boundaries are crossed. Meanwhile, Heliandra devises a phenomenal scheme to send a sand double of herself to find Anatat, but cannot deter her from her path to find Osir...