Alexandra Bracken

Tamsin Lark didn't ask to be a Hollower. As a mortal with no magical talent, she was never meant to break into ancient crypts, or compete with sorceresses and Cunningfolk for the treasures inside. But after her thieving foster father disappeared without so much as a goodbye, it was the only way to keep herself--and her brother, Cabell--alive. Ten years later, rumors are swirling that her guardian vanished with a powerful ring from Arthurian legend....

Violin prodigy Etta Spencer had big plans for her future, but a tragedy has put her once-bright career at risk. Closely tied to her musical skill, however, is a mysterious power she doesn't even know she has. When her two talents collide during a stressful performance, Etta is drawn back hundreds of years through time.