Queen Regent Jiso has Ah Ro brought to the palace, where she informs Ah Ro that she plans to make her a Wonhwa. She asks if Ah Ro knows what happened to the previous Wonhwa leaders, Nam-mo and Joon-jung, and Ah Ro repeats the story told to the people, that they killed each other from jealousy.
The queen regent laughs and says that in fact, she killed them when they became an obstacle to the king's power. She tells Ah Ro that she will use her to regain power over the Hwarang, but that if she becomes an obstacle, she has no compunctions killing her, too.
Ah Ro is terrified, but she tells the queen regent that until the day she dies, she will withstand everything the queen regent throws at her. The queen regent retorts that false hope also kills, but Ah Ro returns that sometimes even a fish caught in a net makes it back into the river.
Sun-woo runs to the palace when he hears that Ah Ro was taken, and he finds Hwi-kyung to ask what he can do to free her. Hwi-kyung tells him of the queen regent's plans for the Wonhwa, and that she will probably kill Ah Ro when she's no longer useful, as she did once before.
This just feeds Sun-woo's panic, and he grabs Hwi-kyung and yells for him to tell him what to do. Hwi-kyung asks if he's willing to become the king, and grabs Sun-woo's hand. He says fervently that by becoming king, Sun-woo can save Ah Ro, and avoid losing his own life as well.
Sun-woo asks who Hwi-kyung is to say all this, and Hwi-kyung says that he's "someone who knows your father well." Sun-woo asks in a whisper who his father is, and Hwi-kyung answers that if he's Sun-woo, then it's Ahn Ji-gong. If he's Sammaekjong, then his father is King Galmoon. "But if you are the nameless peasant Dog-bird, Moo-myung, you are my son. I am your father."
Once alone, the queen regent thinks back on her decision to kill Wonhwa Joon-jung, and how Joon-jung had pleaded for her life. Now we see that Joon-jung had been pregnant, and had told the queen regent that the baby was of the Sacred Bone. She had sworn never to name him, and make sure he lived never knowing who he truly is, if only Queen Regent Jiso spared their lives.
The queen regent had pierced Joon-jung over her heart, crying that the baby can never be born. But Joon-jung had gasped that the baby was moving, and at that same moment, the queen regent had felt life stirring in her own belly. She'd dropped the sword and sunk to the floor, sobbing.
Ah Ro is taken to a room in the palace, where Princess Sookmyung comes to speak with her. She tells Ah Ro that being a Wonhwa is an honor, though it's an honor Ah Ro would happily forego. Ah Ro pleads to be allowed to go to Hwarang to say goodbye, but Sookmyung doesn't answer, and only orders her ladies to make Ah Ro presentable.
In the lecture room, Ji-dwi thinks back on his confrontation with his mother in the throne room, and her ugly words about how unready he is to assume his throne. He recalls Hwa-gong advising him to endure whatever he needs to endure in order to become king.
Hwa-gong is summoned before the queen regent, who informs him that she is reinstating the Wonhwa system. She calls in Princess Sookmyung and Ah Ro, now dressed in fine clothing and jewelry. The queen regent says that the two ladies will leave to pay tribute for four days, then return and become the leaders of the Hwarang, taking over Hwa-gong's position.
At the queen regent's command, Hwa-gong bows low to Sookmyung and Ah Ro, but he asks if this is really the best thing for the Hwarang. She says that she wants the Hwarang to kneel before her, and he tells her that the Hwarang are not what she thinks they are, and that her plan will never work.
Sun-woo paces the Hwarang grounds, the realization that Hwi-kyung is his father echoing in his thoughts. He goes to see Hwa-gong, and asks if he saw Ah Ro when he went to the palace. Hwa-gong says she appears to be fine.
Sun-woo yells at him, demanding to know why he's not doing anything to get Ah Ro away from the queen regent. Hwa-gong says there's nothing he can do, so Sun-woo asks, what if he becomes powerful? With desperation in his eyes, he asks if a king can avoid these situations.
Dan-se escorts his grandfather, Minister Seok, to Minister Park's home. Minister Seok rushes over to speak to Minister Park, who refuses unless he's brought him the king's head. To garner a bit of favor back, Minister Seok kneels in the dirt to offer himself as footstool so Minister Park can mount his horse.
Dan-se is surprised to see his grandfather willingly humiliating himself. He helps him up, and Minister Seok says that Dan-se must bring him the head of the king (whom he still believes is Sun-woo).
Han-sung cheerily calls for Sun-woo all over the barracks, ignoring Yeo-wool's hissy fit at being overlooked. He finds Sun-woo sitting outside brooding, and bounces over to tell him that he's going to write a letter to his grandfather saying how he feels about the way he treats Dan-se.
Sun-woo asks what prompted this burst of self-esteem, and Han-sung says earnestly that he wants to be more like Sun-woo and make his own path in life. Sun-woo throws an arm around Han-sung and says he'll walk that path with him, which makes Han-sung's entire year.
Pa Oh reports to Ji-dwi that Sookmyung and Ah Ro are making a pilgrimage to Nam-mo's shrine, and informs him that some say that Joon-jung was framed for Nam-mo's murder. Her body was never found, so some even think she's still alive. Pa Oh says this is Ji-dwi's chance, and Ji-dwi instructs him to rescue Ah Ro while they're returning from the shrine, and send her out of his mother's reach.
Ban-ryu makes googly eyes at Soo-yeon over the wall, and he reaches out to touch her face, but pulls back. When she asks why, he says that looking at her is already too much, that he may be punished if he dares to touch her.
Soo-yeon puts a hand on Ban-ryu's face and says she'll take the punishment, making him smile like a lovesick boy. She puts her other hand on his other cheek and says she'll take it twofold, then brings him in for a kiss.
Later in their room, Su-ho busts Ban-ryu mooning at the pouch containing Soo-yeon's braid. He admits that he likes Su-ho's sister a lot, and Su-ho grabs him and says their fathers will never permit them to be together.
Su-ho tells Ban-ryu to stop before they both get hurt, and Ban-ryu asks if he's really that worried about him. Su-ho claims that he's worried about Soo-yeon, but it's clear that he cares about Ban-ryu as well.
Han-sung receives a package, and when he opens it, he finds that it's actually for Dan-se. He takes it to his hyung, who acts strange and jerks it away when Han-sung wants to see what it is. Han-sung squeals happily when he sees Sun-woo heading to class, and sends Dan-se a sunny wave goodbye. Why is this giving me such a bad feeling?
Dan-se watches him go, and recalls the rest of his conversation with his grandfather. Minister Seok had told him that if they couldn't join Minister Park's family, that he would kill himself and Han-sung. Dan-se had asked what Han-sung did to deserve that, and Minister Seok had said that he would never allow Han-sung to be anyone's step-stool the way he was forced to be.
Dan-se had asked if that was a threat, and Minister Seok had held out a vial of poison. He told Dan-se to put it on his sword, and one nick would kill Sun-woo. He'd told Dan-se that if he failed, he and Han-sung would both drink the poison.
Dan-se finds Sun-woo practicing his swordsmanship, and asks him to spar. He insists they do it now, and though Sun-woo seems to sense something is off, he agrees. While he's choosing a sword, Dan-se pours the poison on his blade.
They begin, and Dan-se offers Sun-woo an apology in advance. Sun-woo reminds him that it's not necessary, that they're equals, then Dan-se attacks.
Sun-woo is surprised at Dan-se's vicious attacks, and he's further confused when Dan-se tells him to avoid even the tiniest nick. He asks why Dan-se is being so serious when he's the better swordfighter, but Dan-se just tells Sun-woo to kill him if he can, and he will do the same.
He charges, and Sun-woo manages to fend off his attacks until Dan-se slices off part of his clothing. He bellows at Dan-se, who says he talks too much, and goes after him again. Dan-se sends Sun-woo's sword flying out of his hands, just as Han-sung comes into the courtyard and sees them fighting.
We see that Han-sung had opened the note to Dan-se, and read the words from their grandfather: "You must kill him." Seeing Dan-se's expression as he levels his sword at the unarmed Sun-woo, Han-sung suddenly understands what the letter meant.
Dan-se charges, and Han-sung throws himself in front of Sun-woo, catching Dan-se's blade with his hands. Dan-se looks horrified to see the blood dripping from his sword, but Han-sung refuses to let go for fear that he'll try to kill Sun-woo.
Han-sung's voice is beginning to falter as he asks why the oil their grandfather sent is on Dan-se's blade. Sun-woo catches him as he slumps to the ground and starts to convulse, and he asks his hyung, "Why did you do it, Dan-se? You are a good person." Oh, make it stop, this is breaking my heart.
Sun-woo screams at Dan-se, asking what he did, and Dan-se whispers the word "poison." Sun-woo lifts Han-sung and runs with him to find help, and all Dan-se can do is fall to his knees in horror at what he's done.
As Sun-woo carries him, Han-sung's voice weakens as he swears that Ah Ro will fix him up just fine. Sun-woo begs him not to give up, and Han-sung reminds him of his promise to walk with him. He begs Sun-woo not to hate Dan-se for this, and then Sun-woo realizes that Han-sung has stopped breathing.
Sun-woo sinks to the ground, still cradling Han-sung in his arms. He holds Han-sung close and sobs, then gently carries him to the lecture room, where Hwa-gong and the other Hwarang are gathered for class. Sun-woo lays Han-sung on the floor, and the Hwarang gather around them, realization slow to dawn. Yeo-wool kneels and starts to cry, looking to Hwa-gong to tell them he's not gone, but it's too late.
Dan-se finds a secluded storeroom, ready to take a broken pot shard to his wrist. But the door opens to reveal Sun-woo, who says that he asks Dan-se not to die. He says that he understands how Dan-se feels, and gives him the letter that Han-sung wrote to their grandfather before he died, saying that it feels as though it was really meant for him.
Dan-se takes the letter as if it's the most precious thing in the world, and Sun-woo leaves him alone to read it. Before he goes, he says that Dan-se is still his Nando.
Dan-se reads Han-sung's letter to his grandfather: "At first you forced me to come here, now I've come to like living here. From a friend, I've learned that a path that doesn't exist can become a reality. One by one, if a person leaves their footprint, if you can travel together, even a rough path becomes a path.
The reason I'm writing this letter is because from now on, I'd like to tell you that I will receive the punishment that I deserve. Hyung hasn't done anything wrong. Social status, bone rank, though I may not know much about those things, Hyung is just my hyung. He's the most trustworthy person in the world who's on my side."
Dan-se finishes the letter and wails in grief, while the Hwarang gather to bid farewell to Han-sung. They all cry as Hwa-gong says that there are those who would like to shake up the Hwarang, and believe that their way is the right way.
He tells them never to lose a friend this way again, or to be treated as a horse on someone else's chessboard, as we hear the conclusion of Han-sung's letter: "Grandfather, I'm learning how to be an adult in this place. Not leaning on anyone, and taking responsibility for decisions I've made. I even met a Hwarang hyung who said he'd walk the path together with me. I will live freely. Without thinking of family or power, I will live as a Hwarang."
Queen Regent Jiso sees Han-sung's death as another mark in their favor, since now everyone will really believe that Sun-woo is the king. Hyun Chu is concerned that he people are beginning to look forward to Sun-woo as their king, but the queen regent ignores his concerns.
Minister Park arrives unannounced, and wastes no time getting to his point — he's insisting that she abdicate. He brings in his followers on the royal council, who all call for her immediate abdication.
Hwi-kyung goes looking for Ji-gong, who tells him of the horrible things he saw in the low-born village. Hwi-kyung tells Ji-gong of Ah Ro's being made a Wonhwa while he was gone, likening the current political situation to the plague — the country is sick, with no medicine to cure it.
He asks if Ji-gong will use toxic herbs to end the pain, as he did in the village. To clarify, he states that they need to make his son, Hwi-kyung's son, the king.
Ah Ro plays an intense game of Yut with her ladies' maids, dispensing forehead-flicks when she wins. Princess Sookmyung interrupts and criticizes her for playing when her "brother's" life is in turmoil. Ah Ro says confidently that Sun-woo is safe, because she believes in him.
She says that Sookmyung will use any excuse to try and provoke her, but she won't fall for it because she has to survive. Outmaneuvered, Sookmyung just says they are leaving the next day for Nam-mo's shrine.
Ji-gong shows up at the palace to confront the queen regent about making Ah Ro a Wonhwa. The queen regent says it's an honor that she could be head of Hwarang, but Ji-gong knows this is just another way of playing with him.
The queen regent admits that she'll do anything to protect the throne, but Ji-gong declares that her son will never be king. He says that he plans to make Sun-woo the king, and it infuriates the queen regent to think of low-born blood sitting on the throne. But Ji-gong informs her that Sun-woo is qualified to be king, because he is Joon-jung and Hwi-kyung's son.
The following morning, Ji-dwi goes to Hwa-gong and tells him that he didn't have the stomach to woo Minister Park to his side. Hwa-gong asks how he intends to protect the Hwarang when he can't even protect the friend pretending to be king in his place.
Ah Ro is dressed in the uniform of the Wonhwa, and Princess Sookmyung comes to collect her for their pilgrimage. They go to Nam-mo's shrine, and Sookmyung recalls overhearing her mother telling Hyun Chu that their enemies will make a move while they're there. She'd sent him after them and told him not to make any mistakes.
After paying their respects at the shrine, Sookmyung says that Nam-mo and Joon-jung were just like her and Ah Ro — one was a princess, and one a half-breed. Ah Ro asks if she was made a Wonhwa because she saw the king's face, or because of Sun-woo who is pretending to be king.
The princess says that it's not because of anything she's done, but because she's useful to them. She says that Ah Ro is holding Sun-woo back, and that if she stays with him, his life will be in danger, and that he won't be able to move on to greater things.
Walking outside the shrine alone, Ah Ro thinks about all the times that Sun-woo nearly died because he was saving her, and she knows that there's truth in Sookmyung's words. He's even forced to pretend to be the king because he spoke up in Baekje, to prevent her being killed.
She looks up and sees that Sun-woo has followed them here, and the two of them stand looking at each other. Ah Ro asks if this is a dream and how he knew she was here, and he says that he will find her wherever she is and keep her by his side.
He moves to come even closer, but Ah Ro suddenly gasps and runs past him. She throws herself in front of the arrow meant for Sun-woo, and it pierces her in the heart. Sun-woo catches her as she falls and begs her to open her eyes, but she doesn't respond.
The queen regent sits on her throne, shaking at the thought of Ji-gong's threat to put Sun-woo on the throne. She's pale and she coughs weakly, barely able to hear the royal council's demands that she step down. They yell that the country needs a strong king who can guide them in the oncoming war with their neighbors, and they all turn in surprise as the doors are flung open wide.
Dressed in his royal red robes, Ji-dwi strides into the room and straight to the throne. He ignores the council as they wonder who he is, then turns to face them. In a commanding voice, he announces, "I am the king of Silla, Jinheung."