Sixteen-year-old Eva is a princess, born with the magick of blood and marrow - a dark and terrible magick that hasn't been seen for generations in the vibrant but fractured country of Myre. Its last known practitioner was Queen Raina, who toppled the native royalty and massacred thousands, including her own sister, eight generations ago, thus beginning the Rival Heir tradition. Living in Raina's long and dark shadow, Eva must now face her older sister, Isa, in a battle to the death if she hopes to ascend to the Ivory Throne - because in the Queendom of Myre only the strongest, most ruthless rulers survive.