The modern young man Jiu An travels back to the end of the Sui Dynasty and inhabits the body of a little beggar in Taiyuan. At a time when the realm is in chaos and flames of war rage everywhere, he joins Li Shimin's ranks, relying on his knowledge of history, and starts out as the lowest-ranking soldier. On the battlefield of this turbulent age, where death lurks at every turn, he awakens a talent that makes him stronger with every battle. With his bravery and strategic ingenuity, he forces a heavily fortified army to surrender beneath Xihe City, then cleverly provokes the defending general during the Battle of Huoyi and helps the main army break through the pass. Step by step, he grows into a fearsome warrior who strikes terror into enemy forces and earns Li Shimin's admiration. All he wants is to follow a wise ruler and bring the troubled times to an end as soon as possible, so that the displaced people can once again live in peace.