Realm of the Ice Queen - Book Four

Peace is fragile. Secrets run deep.
Only courage can stop a world war and the rise of an ancient menace from the depths of Aereopolis. Belle and Rett's daring saga is far from over.

While Rett labors to restore the capital after the destruction by Dr. Krakov's automatons, Belle takes an airship to Icelandia hoping to forge a fragile treaty, as a war threatens to ignite across nations. But the ice queen there has a hidden secret that will thwart her mission. In the frozen halls of power, she must rely on old friends to help confront the secret that waits to unravel everything she holds dear.
Deep below Aereopolis, Rett uncovers a force more lethal than war-an ancient terror stirring after a century of silence. With enemies closing in and time running out, Belle and Rett must rally old allies and trust their wits to prevent a catastrophe that could end civilization itself.