Kingdom of Agartha: Roar of the Sky

Beneath the ice lies a secret the world was never meant to uncover. In 1947, during the covert Operation Highjump, an ancient spacecraft was discovered buried deep beneath the frozen wastes of Antarctica-its existence concealed from the world for decades. Seventy-eight years later, Rebecca Wilson and her husband embark on an innocent expedition to a remote cave in northern Thailand. But a single wrong turn draws them into the fabled Kingdom of Agartha-a hidden realm at the Earth's core, home to a civilization far older and more advanced than humanity ever imagined. Here, they uncover long-forgotten truths about ancient empires, forbidden technologies, and the shadowy alliance that once existed between surface dwellers and the Agarthians.
Yet not all within Agartha welcome their arrival. A faction of zealots seeks to breach the surface, armed with a devastating relic from the past-the Roar of the Sky, the weapon that once sank Atlantis. As the boundaries between myth and reality blur, Rebecca and her husband must navigate a world of wonder and danger, where the fate of two civilizations hangs in the balance.