一念关山

Ren Xin is sent to prison on suspicion of killing the empress. After that, she fakes her death and escapes to Wu. She lives with a blind lady and changes her name to "Ren Ru Yi". Ru Yi intends to rest and recuperate. However, she's selected by the Crimson Guard Branch in Wu to become a White Sparrow, one of the lowest-ranking members. Thus, she uses that fact to her advantage and pretends to be an ignorant White Sparrow. She intends to locate the culprit who harmed Empress Zhao Jie once her inner force recovers.

Everyone from Six Realms Hall begs Ning Yuan Zhou to stay after his return. Ning Yuan Zhou knows he is badly hurt and should retire. When everyone leaves, Yuan Lu blames Ning Yuan Zhou for hiding the fact that he is still alive. Ning Yuan Zhou says nothing and opens the coffin with his palm. Ru Yi who is hiding inside the coffin is knocked to the ground.

It turns out that when the Old Chief was alive, he had arranged a marriage between Official Pei and Ning Yuan Zhou. However, due to Ning Yuan Zhou's imprisonment and exile, Official Pei is married to someone else. As Ning Yuan Zhou ponders how to reject her, Ru Yi appears, acting all affectionate. She grabs Ning Yuan Zhou's arm, pretends to be his cousin, and deliberately calls Ning Yuan Zhou "cousin" while trying to provoke Official Pei to leave.

Ru Yi and Ning Yuan Zhou reach an agreement. Ru Yi is responsible for teaching Yang Ying everything she knows about An. Once she's done, Ning Yuan Zhou has to help her locate the culprit behind Empress Zhao Jie's death. When he finds out that Ru Yi is "Ren Xin", he's utterly surprised even though he's the renowned Ning Yuan Zhou.

Ru Yi and Ning Yuan Zhou meet the other team members. Yu Shi San tries to court Ru Yi. Ru Yi shows his skills and makes Shi San and Qian Zhao concede to her. Since the Crimson Guard and Six Realms Hall have a grudge, Ning Yuan Zhou hides Ru Yi's identity by calling her a Secret Agent from Chu.

Ru Yi originally intends to control Ning Yuan Zhou with the Twin Butterflies, but with the help of Yu Shi San, Ning Yuan Zhou forces the Twin Butterflies out of his body in the next moment. Ru Yi is furious, and for a moment, Ning Yuan Zhou is also unsure how to handle the situation. At night, Ning Yuan Zhou suddenly discovers that Ru Yi is missing. It turns out that Ru Yi has just gone to the hometown of Yu Lang, which is nearby. On the one hand, she wants to use Yu Lang to verify the truth of what Yue San Niang had said, and on the other hand, she is seeking revenge for Ling Long.

Ning Yuan Zhou finds out that Zhou Jian, a cavalry general, is stationing his troops to intercept them. To reduce their casualties, the diplomatic team moves together. They gather information and forge letters to dupe their enemies. Ning Yuan Zhou heads to Zhou Jian's place, duping him by mixing truth with falsehood. Zhou Jian escorts the "fake diplomatic team" out of the pass personally.

Ru Yi and Yu Shi San go to Qingjing Mountain to find a Silver-ringed Snake to save Yuan Lu. When Ning Yuan Zhou arrives, he sees Ru Yi in danger. He pushes Ru Yi away which causes a relapse of his old injury.

The current Right Guard of the Crimson Guard, Jia Ling, listens to the reports from her subordinates. All the evidence ties the death of Yue San Niang and Yu Lang to White Sparrow, Ru Yi, in Capital of Wu. And the Secret Agent of Chu must have disguised herself as Ru Yi. In the end, Jia Ling sends her trusted aide, Zhu Ji, to track down Ru Yi.

While everyone in the diplomatic team is soundly asleep, Ru Yi secretly meets with someone from the Crimson Guard. Prior to this, she intentionally leaves marks on the bodies of Yu Lang and Yue San Niang, aiming to draw out the mastermind behind the murder case in Capital of Wu. Little does she know that her meeting with the Crimson Guard has already been observed by Qian Zhao. Qian Zhao believes that she is a spy for the Crimson Guard and has betrayed the diplomatic team.

Unexpectedly, Ru Yi falls into Qian Zhao's trap. Caught between the two, she finds it increasingly difficult to hold her ground due to her existing injuries. When Shi San learns that she is a Crimson Guard, he joins the fight. In the end, Ru Yi has no choice but to "hold" Yang Ying hostage. Covered in blood, she flees, leaving Yang Ying behind only when they reach the outskirts of the mountains.

Ru Yi's return and rescue of Yang Ying made Qian Zhao, Sun Lang, and the rest set aside their resentment for her. She and Ning Yuan Zhou realize their true feelings too. Ning Yuan Zhou tells Ru Yi that he's willing to have a child with her after the mission is over. They sleep while cuddling with each other.

Since Ru Yi's return, Qian Zhao, Sun Lang, and others have changed their hostile attitude towards her. They even invite her to join them in their planning. Due to the impact of the war between An and Wu, the contact with Six Realms Hall's branch in Capital of An has been blocked. Therefore, Ning Yuan Zhou plans to visit Jinsha House to buy information.

Ru Yi plans to lure the Crimson Guard to He County which is adjacent to Jing City to find out the truth about the annihilation of the branch in Capital of Wu. The general of Jing City is visiting them to deliver a secret letter from the empress of Wu. Ning Yuan Zhou is tasked to welcome him. So, he asks Yu Shi San and Qian Zhao to go to Jinsha House to visit Miss Jin on his behalf.

Ru Yi is shocked when she finds out that her foster mother from Wu has been held hostage by the Crimson Guard. Zhu Ji's subordinate Qiong Zhu threatens Ru Yi with her foster mother's life. In order to save Ru Yi, her foster mother slits her own throat with Qiong Zhu's sword. By the time Ning Yuan Zhou learns about the situation and arrives, Ru Yi, who is injured, is wielding her sword with bloodshot eyes. She swears to avenge her foster mother.

Zheng Qing Yun tries to sway Yang Ying with both affection and reasoning, hoping to convince her to agree to elope and marry him. As Yang Ying begins to sense that something is off, especially when Yuan Lu, who has come to stop him, is harmed by Zheng Qing Yun, she finally grasps the situation. Realizing that he can't control Yang Ying, Zheng Qing Yun is ready to kill her. At a crucial moment, Ning Yuan Zhou and Ru Yi arrive, apprehend Zheng Qing Yun, and expose his lies.

Yang Ying is still unconscious. To avoid arousing suspicion among the people of An, Ru Yi temporarily disguises herself as Princess Hu Yang from Wu, accompanying Lord Li to An to meet the State Receptionist. However, no one expects the State Receptionist to address Ru Yi as "Master" in front of everyone. Ru Yi is stunned. She never expects that her former disciple, Jiu, would turn out to be Li Tong Guang, the Marquis Chang Qing, who is now the State Receptionist.

Ru Yi agrees to meet Li Tong Guang and mentions that Wu is willing to exchange cities for the safe return of their ruler. Li Tong Guang does not give an explicit answer. Instead, he requests Ru Yi to sit down with her eyes closed and for her to keep quiet. Just like what he did in the past, he sat beside Ru Yi's knees and enjoyed the nostalgic feelings he had in the past. Ru Yi is hesitant about acknowledging him when Ning Yuan Zhou pushes the door open and stops Li Tong Guang.

Ning Yuan Zhou smashes the cup and says that Ru Yi is his most respected lover and companion. He says that no matter if it's the female cavaliers under her or Ru Yi, they don't have the obligation to seduce other men. Mr. Du suddenly realizes the truth. Ru Yi and Yang Ying, who were outside the door, had their hearts stirred too.

Right after the diplomatic team reaches the inn, Jin Mei Niang rushes there to meet them too. Ru Yi doesn't understand why Jin Mei Niang didn't tell her the truth about Li Tong Guang when they were at Jinsha House. Jin Mei Niang explains that it's because the feelings that Li Tong Guang has toward Ru Yi are not just an affection between a master and a disciple, but a passion of a man toward a woman.

Ning Yuan Zhou brings Li Tong Guang to the location of the secret passage, instructing Yuan Lu to destroy the passage. Li Tong Guang follows his instructions, ordering the Garrison General to strengthen defenses around Tianmen Pass and promptly reporting the matter to Emperor An. Ning Yuan Zhou can see that, despite Li Tong Guang's eccentric and jealous temperament, he is unwavering when it comes to matters concerning the well-being of the common people and the significant affairs of the nation.

After being inspired by Ru Yi, Li Tong Guang chooses to join hands with Ning Yuan Zhou. To show his sincerity, he even tells him the location where he buried the fallen brothers of Heaven Realm. Feng Xiao Xiao and the team dig up the remains of their fallen comrades on the shoal. They burn their remains on Guide Plains as they pay respect to them with tears in their eyes. The diplomatic team departs once again as they follow Li Tong Guang's swift pace. They hope that they can receive the emperor of Wu as soon as possible.

The ruler of An allows Yang Ying to enter the pagoda to see the ruler of Wu. Yang Ying lived in the cold palace most of her life. She rarely meets her brother, Yang Xing Yuan. Luckily, Ning Yuan Zhou gives her an old token, the Six Realms Hall Ring. Yang Xing Yuan recognizes her at first glance due to that. Her mighty brother has ended up as a prisoner of war. He casts away his pride and begs Yang Ying to bring him home. Yang Ying is shaken by such a sight.

Chu Yue knows an imperial edict cannot change. After they got on bad terms, Chu Yue's father, Duke Chu, asks her to get along with Marquis Chang Qing. That is why she visits Li Tong Guang, but Li Tong Guang still treats her coldly. Both of them part on bad terms once again because of Chu Yue's provocation and rude words.

Ru Yi finally found the culprit who annihilated the Crimson Guard Branch in Capital of Wu. However, before Jia Ling breathes her last breath, she hints that Emperor An is behind the death of Empress Zhao Jie. Ru Yi is shocked. She can't imagine how forlorn Her Majesty felt when she was killed by the person she loved. No wonder Her Majesty told her not to trust a man easily.

Yang Ying always hides her concern from Ning Yuan Zhou and everyone. She only admits she is afraid in front of Yuan Lu who is the same age as her. She is afraid of the violent ruler of An, the death of the envoy group to save his brother, and worries that she might die in An. Yuan Lu smiles and comforts Yang Ying in his own way.

As Li Tong Guang is reconnected to his master, he's much happier. He even saves Chu Yue on the street when he's passing by. Chu Yue sees a rare and gentle side of him. She develops feelings for Li Tong Guang. Ru Yi initiates her revenge plan. She makes the culprits behind Empress Zhao Jie's death pay by cooperating with Li Tong Guang. Second Prince was banished to the border areas while First Prince was reduced to a commoner.

Emperor An rages after hearing about First Prince's death. Not only did he request an extra 30,000 gold taels from the Wu diplomatic team as ransom, but he also blamed his death on the Crimson Guards, who were innocent. He orders Deng Hui to select 20 members and execute them outside the palace. When Ru Yi and Ning Yuan Zhou reach the site, the execution is already in place. During the key moment, Ning Yuan Zhou avoids the crowd and tells Deng Hui that he has a way to save them.

Ru Yi wants to save the White Sparrows so she gives a prescription that can undo the Crimson Guard's poison to Jin Mei Niang and asks her to make many antidotes. At the same time, a separate unit is planning to raid the pagoda. Ru Yi suggests she can discuss the escape route with Li Tong Guang. However, Chu Yue sees the moment Li Tong Guang tries to stop Ru Yi from leaving.

After Yong'an Pagoda is destroyed, Yang Xing Yuan is transferred to another place. The new prison is called Donghu Cottage which is located on an island. Ru Yi had been there before. With her help, Ning Yuan Zhou and his men make a meticulous plan to rescue the emperor.

After forging a sword from meteoric iron, Ning Yuan Zhou tempers the sword with his blood. Ning Yuan Zhou personally crafts a sword as a gift for Ru Yi. Touched by the gesture, Ru Yi names the sword "Mundane World". They promise to spend the rest of their lives together and to meet outside Capital of An after completing their respective tasks.

Facing the officials and people of An under the city wall, Ru Yi interrogates Li Sun. She forces him to tell the truth behind Empress Zhao Jie's death five years ago. First, she tells the people about Li Sun's crime of colluding with their enemy. Second, she wants Li Sun to promise to record the contributions of the Crimson Guard into the historical records.

Ning Yuan Zhou arrives at Liuli Fort of An which is far away from Capital of An after days of traveling. Under Qian Zhao's careful treatment, Yang Xing Yuan finally regains his consciousness and hands over the Vengeance Edict to Ning Yuan Zhou. Now, Ning Yuan Zhou's mission is complete. He bids farewell to his friends. Shi San, Qian Zhao, and the others will escort the emperor back to Capital of Wu. Meanwhile, he has to return to Capital of An because there's no news about Yang Ying, and Ru Yi is not at the designated location as agreed. The outcome is grim.

Li Tong Guang retrieves Ru Yi's ash from Deng Hui's place. He builds a burial mound for her in the secret cave hideout they shared when they were young. That night, Yang Ying heads to the cave in secret to pay her respects to Ru Yi under the protection of Li Tong Guang's bodyguards. A group of masked assassins attack them. They were sent there by Royal Consort Chu. Yang Ying can't fend them off. She extinguishes all the torches and hides behind her tomb. Right when she's about to be killed, a mysterious woman appears and fights the masked assassins.

Only Yu Shi San, Yuan Lu, and Sun Lang are left in the unit. They don't have much time to feel sad. All of them go to He County to make a report. Yang Xing Yuan is also willing to risk being captured by the An people and defend He County with Wu Qian. There are fewer than 1,000 soldiers in He County and the number of invading Northern Pan soldiers is a few times more than theirs. During this critical moment, the unit and Six Realms Hall's remaining guards stay and swear to protect Hua Xia with Yang Xing Yuan and the people of He County.

Ning Yuan Zhou and Ru Yi find out about Northern Pan's attack on He County at one of the branches. Both of them think Li Zhen Ye and Li Sun are involved in this. He County is in danger. If they don't force Li Sun to send troops, the people of An, Wu, and even the Central Plains will suffer and be miserable. So, both of them turn around and head towards Capital of An.

During the coronation, Ru Yi wears a skin mask and disguises herself as a normal servant. She manages to hold the second price, Li Zhen Ye, hostage. Meanwhile, Ning Yuan Zhou arrives on a white horse and everything becomes chaotic. They expose what Li Zhen Ye and Li Xun did from colluding with Northern Pan to betraying the country for their personal gain in front of all of the officials. They force Li Xun to write a Penitence Rescript and send his army to take down Northern Pan.

As the defeated party, Lord Zuo Xian of Northern Pan personally presents his jade seal to Yang Xing Yuan and Duke Chu, the now-titled Lord Sha Xi, signifying his surrender and respect in the city of He County. However, amidst the cheers of the crowd, the box containing the jade seal suddenly explodes, causing the instantaneous demise of Yang Xing Yuan and the Duke Chu. Ru Yi and Ning Yuan Zhou are aware that there is something suspicious about this incident, and the biggest beneficiary may be in Capital of Wu.

Before their departure, Zhang Song delivers the antidote for the Ten-day Poison to Ning Yuan Zhou. Xiao Yan is amazed by Ru Yi's heroic actions. She gifts her hairpin to Ru Yi, making it convenient for her to act in the future. When both of them rush to He County with the brothers of Six Realms Hall and their soldiers, Chu Yue, Yang Ying, and the rest rendezvous with them while leading the Sha Xi Army and Imperial Guard.

The fourth member of the squad, the most carefree Yu Shi San who likes to joke around with Ning Yuan Zhou is killed in He County. Ning Yuan Zhou stands in the middle of the inn in He County. In his mind, he sees Yuan Lu, Qian Zhao, Sun Lang, and Yu Shi San in white, fooling around in the snow. Ning Yuan Zhou's eyes fill with tears. And he makes a promise to Ru Yi that both of them will stay safe and sound.