Lin Xuan, a top modern-day special forces soldier, unexpectedly travels through time and becomes the substitute for the Crown Prince of the Great Qian Dynasty. The original body was brutally killed in the dungeon, and the real Crown Prince intends to make him take the blame, even using the Crown Princess as bait to tempt him. With his back against the wall, Lin Xuan kills the real Crown Prince in a counterattack. After the Crown Princess discovers his secret, he persuades her to join him in plotting their survival by taking the Crown Prince's place. The Third Prince, the Duke Who Guards the Nation, and other powerful figures conspire against them, while one crisis after another unfolds, including bloodline verification and corpse searches. Relying on the courage and strategic skills of a special forces soldier, Lin Xuan repeatedly overcomes these challenges. He battles powerful ministers, investigates corruption, develops workshops, and trains a new army. Amid the perilous struggle for the throne, he gradually gathers his own forces, transforming himself from a mere puppet substitute into someone who shakes the imperial court and steadily advances toward the pinnacle of power.