The Guardian

A hidden universe, known as the Shadowlands, threatens ours with darkness and magical violence. To protect both worlds, boundary lines were drawn. No one can cross from one world to the next without risking open war. After the fire that killed Tavin's mother, his grief-stricken father disappeared, abandoning him and his sister Moreanna. Tavin and Moreanna share a secret psychic connection. Sometimes, her presence is the only thing that keeps Tavin sane. When a mysterious sickness threatens Moreanna's life, Tavin's connection to his sister begins to fade. With the discovery of a magical universe through a hidden door in his grandfather's attic, Tavin desperately hopes a cure may be within his grasp. "No trespassing" is an easy rule to break . . .