Three hundred years ago, the Great Xia Dynasty lost the gateway to the Central Plains, the "Yanyun Sixteen Prefectures," and since then, the invasion of the Hu people to the south has been unstoppable. In order to seek peace, Daxia signed a treaty with the Hu court - Beimang, paid annual coins, and bowed down as a vassal. Beimang relied on the indemnity of Daxia to continue to grow, but Daxia accepted the humiliation of "ceding territory" and gradually declined, no longer having the ambition to advance in the Northern Expedition Three hundred years later, the Northern Mang forces were unstoppable and decided to completely annex Daxia. The Great Battle of Mangxia was about to break out. At this time, Su Muyang, the Purple Micro Star who was entrusted by heaven, was reincarnated into the human world and became the owner of the mysterious organization Beidou - Emperor Star. In order to deal with the Northern Mang, Su Muyang concealed his identity and became the son-in-law of the Ye family, who were guarding the border town. He secretly helped the Ye family defend the city while preparing for the Northern Expedition The Great Battle of Mangxia officially began, and the Northern Mang vanguard army was unstoppable, attacking the last defense line of Daxia, Wushengguan. Daxia was in imminent danger, and when all the soldiers at Wushengguan were helpless, Su Muyang, as the leader of the Huotou Army, offered a desperate plan to kill the enemy general, turn the tide, and save Daxia When he returned to the border town, he was falsely accused of colluding with the enemy and betraying the country by Qin Feipeng, a prince of the capital who admired his wife. On the day of Ye's birthday, Qin Feipeng forced Su Muyang's wife to divorce him. Su Muyang's mother rushed to stop him, but was still humiliated by him as a spy of Su Muyang. Just as his mother was about to be killed, Su Muyang arrived. Su Muyang told the truth to everyone in the Ye family, but no one believed him. Even his wife wanted to kill him. After he severed ties with the Ye family, the victorious soldiers of Wushengguan returned, proving his identity Afterwards, Su Muyang successfully conquered the sixteen states of Yan and Yun during the Northern Expedition by strategizing, beheading enemy generals, and capturing treacherous officials