As the Arctic glaciers melt at an accelerated pace due to global warming, a mysterious realm that has been frozen for thousands of years - the "Arctic Utopia" (also known as the "Open Arctic Sea" and "The Land of the Ultimate North") - is reappearing in the world. This is not only a geographical phenomenon, but also means that a lost super-ancient circulation system that connects ancient civilizations around the world and the secrets it protects - which may be a civilization, a force, or a portal (from the Abyss) to the core of the earth (or other dimensions) - are about to awaken. Modern humans must solve the mysteries of history while facing the unknown opportunities and huge crises brought about by this reappearing "Secret City"...
