The birth of the sky curtain system, the guardian of human civilization on earth, opened the era of civilization leap and war with endless chaos and strife. Troubled times, powerful people, mysterious technology, infinite scenery... Evil is always hidden in the appearance of the blue sky. Next. The truth, forever buried deep in the shattered sands of the long river. The brightest disaster star under the starry sky? The retreat of the sinner is the beginning of the journey.