For a thousand years, humanity has believed that the moon protects them from the darkness beyond the world. They were wrong. Seventeen-year-old Elyan Vale has always been different. He hears whispers no one else can hear, dreams of places that don't exist, and carries a strange silver mark that appears only beneath the full moon. But when the moon suddenly turns black, Elyan discovers that these aren't curses—they are warnings. Ancient creatures awaken. Forgotten kingdoms begin to fall. And beneath the earth, an entire civilization that was supposedly destroyed a thousand years ago begins to rise. Nymor, the legendary Kingdom Beneath the Moon, has returned. As Elyan flees his destroyed village with a mysterious young mage and a warrior who doesn't trust magic, he uncovers a terrifying secret: his bloodline was created to guard the prison keeping Nymor sealed away. But history has been lying. The people of Nymor weren't monsters. They were betrayed. And the mysterious ruler known as the Moon King may not be the villain Elyan was taught to fear. Now Elyan faces an impossible choice. He can restore the ancient prison and condemn an entire civilization to another thousand years of darkness—or break the seal and unleash a kingdom powerful enough to change the world forever. But there is one thing nobody has told him. Elyan isn't the key to stopping the Moon King's return. He is the key that will set him free.