Christina Diaz Gonzalez

Conor, Abeke, Meilin, and Rollan — once Heroes of Erdas — are now wanted fugitives. Framed for a crime they didn't commit, they've been hunted across the globe by the ruthless mercenaries, the Oathbound. The four friends have traveled to the deserts of Nilo seeking answers, along with an ancient and powerful relic that's connected to the history of their world. There they discover a vast, secret library dedicated to preserving the wisdom of Erdas....

Just after Cassie Arroyo found the Spear of Destiny in Rome, it was stolen from her, so now she and her friend Asher must recover it--but when she used the Spear before she set the world down a dangerous path, and if she recovers it she will have to decide whether to risk using it again.

"Katrina doesn't know any of the details about her past, but she does know that she and her parents are part of the Witness Protection Program. Whenever her parents say they have to move on and start over, she takes on a new identity. A new name, a new hair color, a new story. Until their location leaks and her parents disappear. Forced to embark on a dangerous rescue mission, Katrina and her new friend Parker set out to save her parents--and find...

Ani, a twelve-year-old Basque girl, and Mathias, a fourteen-year-old German Jew, become friends and then spies in the weeks leading up to the bombing of Guernica in April 1937.