War of the Twin Swords - Gemstone Massacre series prequel, #0

On the night before her Choosing, there were whispers of war in the air. After binding herself to Clarent, Opal is given a grim prophecy of her future. Alone and ostracized from her clan, she finds an unlikely ally in the sorceresses' leader, Joan. Joan is the reason the Sorceress clan wants to attack. She's prophesied to pull Excalibur from its stone. But her clan wants its powers for a darker purpose.
They have to band together to stop the Sorceress clan's invasion. Excalibur is on their side, but they're outnumbered five to one. Can Opal escape this war unscathed? Or will her prophecy come true? If you like Merlin and Once Upon a Time, then you'll love the first book in the Gemstone Massacre series. Buy "War of the Twin Swords" today!