In the third century AD, the three kingdoms of Wei, Shu, and Wu were in power. After Liu Bei's death, Zhuge Liang actively prepared for war with the intention of the Northern Expedition.During a military operation, he learned that Zhang He's tribe planned to conduct a decisive battle through Wating and Xiaoguan.In order to deal with this threat, Zhuge Liang decided to send elite troops to guard Fanxudao and key street pavilions.Ma Su recommended himself to guard the street pavilion, and Zhuge Liang appointed Wang Ping as his deputy general to accompany him.

However, there was an error in the intelligence.Zhang He's tribe actually chose Fanxudao to attack Jieting. Due to Ma Di's negligence, the entire army was defeated and Jieting was lost, putting the Shu army into a situation where it was attacked from both sides.Zhuge Liang had no choice but to retreat to Hanzhong.This defeat was a heavy blow to Shu, but it was a rare victory for Cao Wei.

Guo Gang, the governor of Tianshui County, felt very proud when he saw the army entering Tianshui one after another.His chief secretary Chen Gong also flattered him and praised him for his great achievements in Longxi.However, Ma Di could not escape the responsibility for the loss of Jieting. Although Li Miao tried to dissuade him from joining the army, Zhuge Liang finally ordered Ma Di to be beheaded due to military law.

Shi Yangyi, the Prime Minister's Office Director, realized that the loss of the street pavilion was closely related to the inaccurate intelligence, and suspected that spies from Wei had infiltrated Si Wencao, the intelligence department of Shu.In order to find out the truth, Zhuge Liang ordered a thorough investigation of the matter, and Bai Long, the Shu spy agent who provided the intelligence, became a key figure.

In Tianshui City, a man dressed in ordinary clothes learned of the meeting place with Bai Long through a note.However, all this is under Wei Spy's control.When the traveling owl from Shu came to join him, he was already being watched by Wei spies who were ambushing nearby.In the end, You Xiao was hacked to death at Niuji Winery.

The failure of the Northern Expedition led Zhuge Liang to ask for demotion. Although Liu Chan did not directly express his anger at him, under Li Yan's words, he still agreed to Zhuge Liang's request.Li Yan had always opposed Zhuge Liang's Northern Expedition and wanted to seize military power.Yang Yi was worried about this, while Zhuge Liang believed that the country should be the most important thing, and cooperation would benefit both sides.

In the territory of Nanzheng in the Shu Han Dynasty, Xunxu, the deputy commander of Jingansi under Si Wencao, was undergoing harsh water torture.He was suspected of being related to the rebellious Shu spy Baidi.Xun Xu firmly believed that Chen Gong was innocent and passed the test.However, he was told to go to Cao Wei to find out the truth about the fall of Jieting and get rid of the rebellious Bai Emperor.After drinking the poisonous tea, he must complete the task within three months before taking the antidote.In this way, Xun Xu, who had never been on the field before, embarked on a journey to Cao Wei with a poisonous dagger.

At the same time, in Tianshui City, Guo Gang became suspicious of Chen Gong.He thought Chen Gong might be Shu Long's spy.Mi Chong also said that the Shu spy's behavior today was very abrupt and he was afraid that someone was warning him.However, Guo Gang defended Chen Gong, saying that he was assigned by himself to deliver the medicine, and that he was imprisoned for seven days afterwards and could not deliver information at all.Facing Guo Gang's temptations and doubts, Chen Gong felt very anxious and helpless.He was worried that his identity would be exposed, and he was also worried that he would not be able to convey the existence of Zhulong to Shu Han.In this crisis-ridden moment, Chen Gong must find a way to resolve the crisis and protect his identity from being exposed.