Rosy is a bone familiar, gifted with the power to shift into animals marked with exposed bone. She spends most of her days in the magical Bone Forest, caring for her feral grandmother and hiding her powers to avoid conscription by the Witch King's army. Until the day that Princess Shaw, a witch known as Death's Heir, visits the Forest. When Rosy saves Shaw's life, the princess offers her the chance to attend the prestigious school, Witch Hall, as payment. Though Rosy is wary of Shaw's intentions, she cannot pass up the opportunity to find the cure for her grandmother's affliction.

But at Witch Hall, Rosy finds herself embroiled in political games she doesn't understand. Shaw wants Rosy for her entourage, a partner to help lead the coming war. All Rosy wants is to stay out of trouble until she can graduate and save her grandmother, but she can't deny her attraction to Shaw or the comfort Shaw's magic gives her. Will Rosy give in to her destiny, or will the Bone Forest call her home once and for all?