In possession of the fish-shaped tally, Chu Yu shows up at the Arsenal Bureau on the premise of needing to see Lu Qiba under Wei Yun’s order, not knowing Wei Yun is presently at the Arsenal Bureau with Lu Qiba. She’s let in and is led to believe that she’ll get her meeting with Lu Qiba with some waiting. Instead, she’s led to a separate reception area where she is surrounded by guards.
Her unfazed look suggests she attempted to take them all down after being locked in. However, the next time we see Chu Yu is in a dark secret room.
Wei Yun also ends up in the secret room after Lu Qiba sends him in there with a crossbow arrow that shoots ropes that Wei Yun fails to dodge. Bounded, Lu Qiba locks him inside with Chu Yu.
Lu Qiba is at odds with Wei Yun over Chu Yu’s possession of the fish-shaped tally which granted her entrance to the Arsenal Bureau. In Episode 2, Wei Jun had mentioned that the Arsenal Bureau was the empire’s critical stronghold. In the same episode, Lu Qiba was mentioned as being so strict about releasing files that Wei Yun was turned away when he wasn’t the commander and was there on behalf of Wei Jun. Allowing Chu Yu to have the fish-shaped tally and get into the Arsenal Bureau, not knowing what she’s after, was no doubt something Lu Qiba found extremely impermissible.
Sarcastic remarks about using the Arsenal Bureau resources to please a woman and calling Wei Yun a romantic when Wei Yun warned Lu Qiba over the way he talked about Chu Yu were thrown at Wei Yun. Lu Qiba hadn’t forgotten the dancer at Fragrance House that had entertained Wei Yun and Hassan instantly recognised Chu Yu to be that dancer despite the masculine outfit she wore.
Wei Yun explains his actions as introducing a fish into the water to stir up the waves for the fishes in the water—that fish being Chu Yu. Seeing as she wants to enter the Arsenal Bureau, he was going to let her and use her to (perhaps) draw the attention of the fisher—that is, the traitor—and lure him out. At the same time, he could catch her and find out what she’s up to. Wei Yun tells Lu Qiba that allowing Chu Yu to obtain the tally is related to the collaboration between him and Lu Qiba—which, unknown to Wei Yun—is actually very true.
Lu Qiba doesn’t relent. He accuses Wei Yun of overstepping his boundaries and interfering in responsibilities that should be his. It’s around this point Lu Qiba whips out a few flying needles to make Wei Yun back up into the position of the revolving door on the wall behind him and fires his crossbow ropes at Wei Yun to bind him and send him into the secret room where Chu Yu was also held.
Lu Qiba moves to let his men know that Wei Yun’s been locked in the secret room because of an accusation against him regarding the leak of the previously discarded blueprints of the octagonal crossbow, which landed in the hands of the North Qi. Everyone was shocked such an accusation was made. Not one of them believed Lu Qiba would sell the blueprints to the enemy for personal gain. It sees them fully support a thorough investigation of the case, vowing to give Lu Qiba their full cooperation.
It looks as if Lu Qiba has gone on his own in the method of flushing out the traitor in the Arsenal Bureau. Lu Qiba has shown to be the type to throw his own wrench in the works to challenge Wei Yun to get himself out of things and achieve goals—for example, when Lu Qiba spread rumours about Wei Yun to see if he could solve the situation and earn his title through support. It’s also possible that the act of locking Wei Yun up in the secret room and announcing a thorough investigation because of Wei Yun’s accusations was the original plan. Wei Yun didn’t call out against Lu Qiba’s actions when he was made to enter the secret room. The method of sending Wei Yun to the secret room by aiming weapons at him, though, could just be an addition on Lu Qiba’s part after discovering Wei Yun had acted on his own with regard to allowing Chu Yu to get her hands on the fish-shaped tally. The exact plan to flush out the traitor was never revealed.
Not a single person stood out during Lu Qiba’s notice of an investigation into every member of the Arsenal Bureau. However, the camera did give a clue, staying on the row of men at the front and sharpening the lens’ focus on the Director of Wei Tongfeng in one shot. The threat of leaving no one out of the investigation indeed lures out this traitor, who is, in fact, Wei Tongfeng. The fact that Wei Yun is confined in the secret room makes it too tempting for him to stand still and not attempt to take Wei Yun’s life. With Wei Yun dead, the investigation would go nowhere, and the investigation can stop.
Before Wei Tongfeng makes his move, it’s Chu Yu who Wei Yun faces attacks from. Not knowing it’s Wei Yun who has joined her, she attacks him with a few sizable rocks found on the ground. He manages to dodge them despite being bound.
Chu Yu somehow manages to keep a knife and starts using it to attack him as well, sneaking up from behind him to attempt a stab on the left side and a swipe towards the right. Both times, she missed. The third attempt up Wei Yun’s back sees her swipe up the ropes, releasing Wei Yun from them.
Arms free, Wei Yun catches her attacking arm, allowing them both to recognise just exactly who their opponent is. They both ask each other the same question, “Why are you here?” This place being the Arsenal Bureau, it’s Chu Yu who should really answer, since she’s the one who’s out of place.
Chu Yu doesn’t give much away about her motive. The only new response is that she’s looking into something before she assures him once again that she won’t harm him or his family. This promise doesn’t do anything to settle the distrust. She did just steal the fish-shaped tally and sneak into the Arsenal Bureau under Wei Yun’s name, so it natural Wei Yun questioned her trustworthiness.
Wei Yun questions her again about her motives. She’s not prepared to answer this question and tries to escape from his hold, but she’s tugged back towards him. Unable to avoid giving a response, Chu Yu remains vague, telling him that she had thought about revealing it to him but implies that she didn’t, as she doubted he’d help her with it.
The confrontation between them ends here, as the mole makes his move. Countless arrows fly out of the walls. It looks impossible to survive with the sheer amount of arrows coming out of the walls, but Wei Yun and Chu Yu do survive.
However, they play dead upon hearing someone enter. It’s the traitor Wei Tongfeng who’s come in to make sure Wei Yun’s dead. Feeling for the breath, Wei Tongfeng smiles. Wei Yun’s dead—or that’s what Wei Yun’s led him to believe, as a moment later, Wei Yun’s eyelids open.
Wei Yun leaps to his feet and holds Wei Tongfeng down. Lu Qiba enters at this point to have Wei Tongfeng know that Wei Yun wouldn’t die because of a traitor like him. He jokes that Wei Yun is not only blessed, but he also has Chu Yu by his side—a “beloved who is like divine help and can turn any misfortune into good fortune”.
It has Chu Yu confused. The reason she’s confused might not be because she’s been referred to as Wei Yun’s beloved, but more that the whole situation was a set mup. Lu Qiba’s smug tone when Wei Tongfeng was apprehended and referring to Wei Tongfeng as a traitor with no shock in the discovery was possibly viewed as a setup by her.
Chu is left in the secret for the meantime while Wei Yun drags Wei Tongfeng before everyone to confess to his crime. Wei Tongfeng tries explaining his actions as following Lu Qiba’s orders, but Wei Yun refuses the explanation. It’s not because of the fact he knows Wei Tongfeng is the traitor, but because his actions were opposite of the actions of a loyal man to Lu Qiba. Wei Yun points out that if Wei Tongfeng were a loyal person, he’d fully assist Lu Qiba to assist him in an investigation to prove his innocence, but instead he went and tried to kill Wei Yun. As mentioned already, this was so that the investigation would hit a dead end and go nowhere. If the investigation were to reopen some day and expose him, Wei Yun suspects Wei Tongfeng would use Lu Qiba as a scapegoat and pin the leak on him then.
Wei Tongfeng stops denying the charge and instead banks on Wei Yun not daring to kill him. With confidence in his tone and stare, he admits to being the traitor before he expresses how only he can give him the name of the person who bribed him, so he won’t dare to kill him nor can he afford to kill him.
How wrong he was. Wei Yun only barely lets Wei Tongfeng finish his words before he stabs the head of the arrow in the traitor’s heart. There are other ways to find out, Wei Yun says. He then leaves the cleaning up to Lu Qiba, who has Wei Shuo do it, seemingly not keen.
Going back to see to Chu Yu, Wei Yun discovers an empty room. She’s managed to escape and has gone back to the Marquis of Zhenguo’s Mansion. Although she’s been exposed, she’s still unwilling to cut her losses and forget about her investigations. Her only hope is to keep denying things and take a gamble on Wei Yun.
Not long after, Wei Yun marches directly into her room. It’s already night when he visits. With the way he marched on in unannounced, maybe he didn’t really expect her to have returned and was exasperated by her audacity in returning to the Marquis of Zhenguo’s Mansion after escaping the Arsenal Bureau.
Wei Yun is once again quite antagonistic, but his response comes off as just wanting her to tell him the truth—to reveal her motives to him. He isn’t closed to hearing her out. He even invites her to do so because, back in the secret room at the Arsenal Bureau, Chu Yu actually saved him when the arrows were released. Chu Yu’s leg actually got grazed by an arrow in the secret room while doing so. So, he wants to give her a chance to explain herself.
Chu Yu doesn’t think she needs to explain anything to him as she believes she doesn’t owe the Wei family anything. She adds that even if she was up to something, it’s something that she can have a clear conscience about. She makes a move to leave.
It sees Wei Yun grab her wrist to stop her. It’s not so much because of her hidden motive and wanting the answer but simply that he’s unwilling to let her go. Chu Yu flicks her wrist to release his grip on her, which sees the crossbow trigger fall out of Wei Yun’s wrist guard and onto the floor.
Everything is out in the open—the reason Chu Yu entered the Marquis of Zhenguo’s Mansion and the fact that Wei Yun is investigating the same case as she was are all clear to them both. It doesn’t settle things between them, though, as Chu Yu expresses feeling like a fool for being used. She thought she had it all planned out and had kept it within her control, but she didn’t expect Wei Jun to entrust Wei Yun to investigate the case.
In his defence, Wei Yun points out that he’s been used by her many times as well. But this fact doesn’t bother him as much as the fact that she trusted Wei Jun with the case but not him. Chu Yu reminds him about the way he had treated her when she first entered the family. She felt like a sword was pointed at her throat, and so she couldn’t see why she should trust him, nor could she see herself betting her life on him.
Chu Yu walks out on him at this point, limping away. She’s once again reluctant to walk away after coming all this way, but she also doesn’t want to stay at the Marquis of Zhenguo’s Mansion after all this. Fortunately, after she leaves, Wei Yun discovers a letter in Wei Jun’s room that expressed his last wish. This was for the person who discovers the letter to aid Chu Yu with her investigation.
The letter gives Chu Yu the means to continue on with her investigation, and it gives Wei Yun the means to keep Chu Yu from leaving his family. Wei Yun is more straightforward about his wants. He sincerely apologises to her about his unfair assumptions about her and explains his reasons for the way he dealt with her while trying to flush out the traitor at the Arsenal Bureau. The crossbow case involved too much (which is a reason not too dissimilar to why Chu Yu didn’t let Wei Yun know). He then directly asks her to stay to investigate the case with him, promising to be honest with her if she does.
Chu Yu, though, wasn’t sure about the approach to take with this sincere Wei Yun before her. She goes with seeing what he’d do if she were to not accept his apology. This gets her into an even more unfamiliar situation—one which sees her even more baffled as to how to proceed. Wei Yun tells her that if she didn’t accept her apology, then he’d wait until she did.
The answer sees Chu Yu faint right in front of him. It looked pretty real, but she was pretending. After she was brought back to her room, she woke to reveal to Wanyue that she had to pull this stunt to get herself out of the situation, as otherwise, she had no idea about how to continue on. She still has her reservations about Wei Yun, but should he regret anything in the future, with the belief that he made her faint, maybe his guilt will hold him off from kicking her out.
The next morning, Wei Yun personally visits with snacks and toys to check up on her condition as well as try to make amends. Chu Yu pretends she’s still asleep and has Wanyue greet Wei Yun instead, but she’s caught peeking behind a door. It amuses him.
Now that he knows she’s awake and listening, he increases his volume, confusing Wanyue as to why he was speaking so loudly with her standing next to him. He wants to pass on a message that he’s sorry for causing her to injure herself (he’s referring to her fainting) after catching her in the act. He also moves to reassure Chu Yu that he will explain everything to Chu Linyang and keep investigating the rest of the case. He wants Chu Yu to not worry about a thing and recuperate.
He has Wei Qiu hand over the snacks and toys to Wanyue to take back to Chu Yu. On the toys were engravings he carved to express a speedy recovery and his desire to work and go through everything together. Wei Yun’s working hard to gain her trust in him.
At the Arsenal Bureau, Lu Qiba tries to make amends to Wei Yun for giving him a hard time, for not submitting to him, and for not trusting him. He tries to use gifts like a paper fan (which is a weapon in disguise) and gets right down to business, like giving Wei Yun his investigation notes on Wei Tongfeng, to show his sincerity. It’s a method Wei Yun sees as comparable to the way Lu Qiba chases women and one which he sees as not enough to erase grievances between them.
Lu Qiba moves to express the reason he was so hard on Wei Yun. He worried he’d ruin Wei Jun’s hard work. This was the honest truth, and it is what Wei Yun is looking for from him. Lu Qiba had moved to try apologising—an act he actually struggled to get out in words—but it wasn’t what Wei Yun wanted and didn’t make him say the words. He values honesty and hopes Lu Qiba can always be honest with him, and Lu Qiba assures him that once he promises or trusts someone (which he now does with Wei Yun), he will always keep his word.
Onto talking about the investigation into the crossbow case, Lu Qiba mentions having followed a man who was said to be someone Wei Tongfeng often met at Spring Breeze House. Who that man is isn’t revealed, but the suggestion is that the man is General Yao Tong (Wu Hong), the general who was with the Crown Prince and almost died. Wei Yun’s train of thought is that if there’s something suspicious with the Crown Prince, then Yao Yong can’t be clean either. There is suspicion that Yao Yong may have bribed Wei Tongfeng.
To obtain this information, Lu Qiba was seen visiting Fragrance House, chatting to a dancer who he promised to sweet-talk differently 300 times if she could give him information about the people Wei Tongfeng saw recently. It was through this promise he managed to obtain a lead to their investigations. The effort he put into getting this lead was something Wei Yun appreciated, earning Lu Qiba a genuine thank you from him.
With Wei Yun gaining Lu Qiba’s respect and support, Wei Yun officially takes command of the Arsenal Bureau. He stands before his men, who all pledge their service to protect the nation and its people and defend their world under Wei Yun’s command.
Ending the episode, Tuantuan is seen checking Chu Linyang’s condition. There are no major issues, just that his meridians are blocked and need improving. The scene reveals Tuantuan being a self-taught physician who comes off as having great potential. She reveals her method of study is feigning illness and learning from imperial physicians in the palace, and she has secretly saved many people with these skills of hers.
She was afraid Chu Linyang was worried to hear her say her skills were all self-taught, but he was not one bit focused on this fact. He was more focused on the countless scars on her wrists that were the result of five years of practicing on herself. Tuantuan felt a bit embarrassed when she had unwittingly revealed the scars, but she saw these scars as proof of the efforts she made to get to the point she has got to.
Chu Linyang shows her his scars he got from his battles against North Qi. He didn’t want her to think he found her scars ugly. Wanting to support her in improving her medical skills further, he offers to be his practice patient, lending her his arm.
Tuantuan is captivated by him and his offer. She breaks herself from her daze to teach Chu Linyang a technique to unlock his meridians.
