Sun-woo confesses his love to Ah Ro and kisses her as Ji-dwi watches them from a short distance away. He goes to shoot arrows the next day, but images of the two kissing, as well as memories of Sun-woo stepping forward and claiming to be the king run wildly through his head until he loses his temper and drops his bow, furiously slamming his sword into the target instead.
Ah Ro takes the little boy who was orphaned in Crown Prince Chang's "hunt" to shopkeeper Joo-ki. Joo-ki whines that he can't take care of a child because he's never even been married ("I am pure from head to toe!" hee), but Ah Ro sends the boy to sit next to him. A touch of a tiny hand and a pair of puppy-dog eyes, and Joo-ki is putty in the adorable cherub's hands.
Ah Ro's friend Soo-yeon is feeling morose these days because Ban-ryu hasn't contacted her since they all came home from Baekje. Ah Ro tells her that relationships have their ups and downs and advises her to wait for him to come around.
Speaking of Ban-ryu, he's stopped by nasty piece of work Kang Sung, who asks if he's deliberately ignoring Minister Park. Kang Sung hands over a note, which says that Ban-ryu worked hard for nothing. Kang Sung taunts that his adoptive father has abandoned him, and laughs when Ban-ryu shouts at him to shut up.
Sun-woo flails adorably when he tries to sneak up on Ah Ro, but Su-ho beats him to it. He grows jealous when the two go into the infirmary, knowing that Ah Ro is about to see another man with his shirt off.
Ah Ro shows Su-ho the arrow that nearly killed him, and fusses at him gently for throwing himself in front of the arrow meant for Sun-woo. Su-ho flinches as she dabs medicine onto his healing wound, and he casually asks if they've really never dated, since he thought he'd dated all of Soo-yeon's friends.
Sun-woo sneaks into the room, and Su-ho awkwardly switches to formal speech, still under the impression that Sun-woo is the hidden king. Sun-woo calls him on it and he switches back to banmal, ha.
On pretense of checking out Su-ho's wound, Sun-woo grabs Ah Ro's hand and takes the ointment from her, and they're so busy gazing into each other's eyes that Sun-woo accidentally presses too hard on Su-ho's back. Sun-woo thanks Ah Ro, but Su-ho assumes he's thanking him and asks why, but Sun-woo just answers vaguely.
Later, the lovebirds stroll through the Hwarang grounds, and Ah Ro confesses how happy she is that there's someone who would be willing to sacrifice his life for her. Sun-woo is touched, and he tells Ah Ro that if she dies, he dies too. He promises to always put her first, so he asks her to help him out and think of herself first, and they pinky-swear on it.
Han-sung witnesses this conversation and squints at the two suspiciously. He tells Yeo-wool that he doesn't think they're really siblings — they can't be, if Sun-woo really is the king.
Sun-woo takes Ah Ro to the river, and pretends there's something in her eye to sneak in a kiss on her cheek. He takes her face in his hands and gives her a more serious kiss, enjoying their bit of alone time.
Princess Sookmyung updates her mother, Queen Regent Jiso, on the events in Baekje, including how Sun-woo claimed to be the king. The queen regent asks what Sookmyung thinks of Sun-woo, and though Sookmyung's memories are pretty swoony, she has the foresight to keep her answer neutral.
She says that Sun-woo is fair and fearless, and a good leader. The queen regent asks if the princess has feelings for him, and Sookmyung denies it, which seems to please her mother. She says that her daughter is a lot like her, though it makes her nervous.
She expresses concern that the Hwarang have gotten too strong and that she's losing her grip on them. She tells Sookmyung that she's making her a Wonhwa (female spiritual leader of the Hwarang), reminding her of the two historical female Wonhwa who fought and were both put to death.
The Hwarang resume classes, and Hwa-gong present a poem for them to study, explaining that poetry can offer a glimpse into the lives of the people and how they feel about their king. He asks Ji-dwi to stand and read it, which he does:
Rat, rat, large rat. Don't eat my barley.
I cared for you for a long time, but you do not care for me.
Surely I will leave you, and go to that happy nation.
Happy, land, happy land,
I will find righteousness there.
Ji-dwi grows emotional as he reads the poem, understanding that the rat is the king, hiding and eating the people's grain. Hwa-gong explains that if the rat eats the people's livelihood, the people will leave, all the while glaring at Ji-dwi. He concludes with, "A king without his people is no longer a king."
Ji-gong is still in the low-born village, despairing that there's nothing he can do to help all of the sick people. Woo-reuk tells him that knows a way to get his hands on some medicine, but sighs that there's no way they could get it and bring it to the village.
When Ji-gong asks why, Woo-reuk asks if he knows why low-borns are banned from coming into the capital. Ji-gong says it's to preserve the bone rank system, but Woo-reuk laughs at him. He says that all of the gold in the city comes from the village, where they pan it from the river. The law is to prevent the low-borns from knowing the true value of that gold.
Ji-gong is horrified that the village is being kept separate out of greed, but Woo-reuk tells him that he can't change anything. Or, he says, Ji-gong could get the medicine.
The entire delegation heads to the palace where Queen Regent Jiso has summoned them to be recognized, and Sun-woo is taken to speak to the queen regent first. She tells him that before the Hwarang, there were the Wonhwa, who were youths who trained in martial arts and maintained order in society. Their leaders were a pair of women, Nam-mo and Joon-jeong.
The queen regent tells Sun-woo that she heard of Ah Ro's role in keeping the peasants hopeful, and that she plans to make Ah Ro a Wonhwa. Sun-woo controls his expression, but he asks darkly, "Am I not enough?" The queen regent admits that she's doing this to control Sun-woo, and orders him to continue acting as though he's the king in order to protect her son.
Ah Ro paces and worries why Sun-woo is taking so long, but Ban-ryu is even more morose than usual. Su-ho asks him what's wrong, but Ban-ryu just tells him to mind his own business.
Ji-dwi walks the grounds and finds a small courtyard with a decorative statue. He reaches into a hole in the statue and pulls out a small wooden horse, something he must have stashed there when he lived in the palace as a boy.
As Ji-dwi is lost in his memories, Princess Sookmyung finds him and demands to know what he's doing here. He quickly stashes the toy in his shirt and says he was lost. The princess doesn't believe him, since it's a pretty secluded spot that even the court ladies don't know of.
Ji-dwi starts to leave, but he stops short when the princess calls out, "Oraboni!" Ji-dwi says she's mistaken, but she stops him with her sword this time. She steps close and studies his face, and asks in a small voice how long he's lived this way (hiding his true identity). He says that she can't imagine how long it's been.
Later, Ji-dwi, Su-ho, and Ban-ryu leave, as Su-ho complains that they didn't even get to see the queen regent. They look up and spot her watching them, and she silently thinks to Ji-dwi, "Are you safe? Are you hurt?" He telegraphs back that he's safe for now, and his mother thinks that the more he disobeys her, the harder things will be for him.
She turns to leave, and Su-ho follows her excitedly. He unthinkingly grabs her arm and she flings out a hand, cutting a shallow groove into his cheek with her ring. Su-ho suddenly realizes he was being disrespectful, so he kneels and introduces himself.
The queen regent remembers him from when she asked him to look after Sun-woo, and she seems to feel guilty when she notices his arm in a sling. But she turns away without acknowledging him, leaving Su-ho confused.
In a different part of the palace, Sun-woo reels at the queen regent's command to continue behaving as the hidden king. She'd told him that he was to be bait, to face any danger that her son would otherwise face. He lets out a scream of frustration, feeling trapped and afraid.
The other three Hwarang are lost in their own thoughts back in their barracks. Ban-ryu thinks about the note from Minister Park, and how Kang Sung had said he'd given up on him. Su-ho wonders why the queen regent pretended not to know him. And Ji-dwi looks at his toy horse and thinks about his conversation with Sookmyung.
Hwa-gong recalls how Crown Prince Chang called Sun-woo "Jinheung," and when his assistant Bu-jae asks what's wrong, he just says this place won't be the same anymore. He goes fishing to work through his thoughts.
Soo-yeon is waiting when Ban-ryu arrives home for a visit. She says that she's been waiting to see him since he came back, but Ban-ryu just tells her not to like a guy like him. He says he's not going to see her again, and goes inside. Soo-yeon calls out to him tearfully, but the door is shut in her face.
Inside, Ban-ryu bows to the floor in front of Minister Park and begs him not to abandon him. He asks for another chance, but Minister Park says he's changed his mind about making Ban-ryu king. He's decided to make himself king, and Ban-ryu offers to help him, no matter what it takes.
Hwi-kyung finds Sun-woo still in the palace and offers him a glass of wine. Sun-woo is surly and suspicious and tells Hwi-kyung to get lost, but Hwi-kyung chuckles at him. He says the people are overjoyed and excited that the world will change now that the king finally showed up.
But he warns that if Sun-woo isn't the real king, their disappointment will be just as great. He asks if Sun-woo might think about really becoming the king, if he could change the world. He offers to make Sun-woo into the king, but we don't hear Sun-woo's answer.
Ji-dwi stands in the classroom, staring at the poem about the people's feelings for the king. He thinks about how Sun-woo stood up to declare himself king in his place and put his own life on the line to save the imprisoned peasants. Tears of shame fill his eyes, and he quickly wipes them away when Hwa-gong joins him.
Hwa-gong talks about the "rat" who couldn't speak up and declare himself king in front of the enemy prince, and Ji-dwi agrees that he's too scared to be the king. He calls himself a coward, always hiding.
Hwa-gong says that there are many cowardly kings in the world, but not many who would call themselves a coward. He says that's its own act of bravery, but Ji-dwi asks if a person like that can really become king. Hwa-gong tells him that wherever he is, if there's something he needs to do as king, then he should do it.
Ji-gong goes to see Minister Park and confronts him about the rumors of plague medicine being hoarded. Minister Park plays innocent, but when Ji-gong asks him to donate his stores of herbs, he scoffs at the idea of giving it away.
He says he's waiting until people's fear is high enough that they'll spend their live savings on medicine — when that happens, he'll distribute the herbs. Ji-gong is astounded that Minister Park would allow the plague to spread to make a profit.
Ji-gong leaves, and Ho Gong brings in Han-sung and Dan-se's grandfather, Minister Seok. Minister Park asks how many true bone are left in the Seok family (answer: not enough), and Minister Seok reminds him of his promise to link their families through marriage.
Speaking of the boys, Dan-se is still helping Han-sung train, though it doesn't look as though his brother is getting any better. Han-sung is drenched in sweat while Dan-se barely moves a muscle parrying his attacks, and he easily knocks Han-sung to the ground.
Han-sung has a little tantrum, wailing that Dan-se is skilled while he doesn't even like swordsmanship. Dan-se says that if he can't beat him in a thousand tries (of which he's already used 991), then he'll leave their household. He tells Han-sung to stop whining and man up, and Han-sung picks up his practice sword and starts again.
After sitting up all night thinking, Queen Regent Jiso calls for Minister Park. She takes him by surprise by telling him that she plans to step down, since King Jinheung proved his readiness to rule by defeating the Baekje crown prince. Minister Park wonders what she's planning as she gloats that she's won and he's lost.
Later, her guard Hyun Chu argues that her son isn't ready. But the queen regent says there will be no abdication — she just needs Minister Park to believe that Sun-woo is the king. She still sees Ji-dwi as a child who isn't ready to assume his throne. Hyun Chu is worried about how Sun-woo will take all this, but the queen regent says he'll have no choice in the matter.
Ah Ro asks her father what will happen to the people if he can't get the medicine, and he says he just has to get it. He says he's glad she came home safe, and Ah Ro tells him that she's worried about Sun-woo now that everyone thinks he's the king.
He's at the Hwarang grounds now, and he joins Ji-dwi as he looks out over the courtyard. Ji-dwi jokes that he's more handsome than Sun-woo expected the king to be, but instead of being angry, Sun-woo just asks softly if Ji-dwi has lived this way all his life. He then amends his comment to say "that king."
He says "that king" must always be worried about the people around him and must be too anxious to sleep, because that's the way he feels now. Sun-woo wonders if the king also thinks about overturning the world, but Ji-dwi says a king who was never treated as a king wouldn't think that way.
Sun-woo asks if the king knows how the people feel, and Ji-dwi says that he lived as one of the people. Sun-woo finally gets angry on behalf of Mak Mun and snarls that the king who lives as a citizen kills anyone who sees his face. Ji-dwi seems equally angry as he agrees that it's true, and that the king probably doesn't even know how many people died because of him.
Ji-dwi spits that the king is stupid and foolish, and too weak to make the killings stop. Sun-woo asks if that king can save the world, or if he even needs to be alive. Ji-dwi says that if Sun-woo wants to kill that king, "…then kill him."
Ah Ro hears footsteps behind her in the infirmary and, thinking it's Sun-woo, she asks if he missed her. But she stands to find Ji-dwi instead, looking gloomy and serious. He asks her if she would run away with him and live an ordinary life with him. He says he has nothing he can offer her, but he'd be willing to exchange Silla's throne for her.
Ji-dwi adds that it's okay if she likes Sun-woo, who he guesses isn't really her brother. He asks one last time if she'll come to him instead, and he'll live not as a king, but as her Jinheung.
Ah Ro doesn't answer his question, but asks one of her own: "Are you using me as an excuse to run away?" She says that he's always asking himself why he has to be king, but that he already knows why, and what he needs to do.
Ji-dwi asks what she knows about it, and Ah Ro tells him that if you look into the eyes of a person who's given up, then you know. She says that he's never given up.
That night, Sun-woo stays up, staring at the stars. Ban-ryu looks over at Sun-woo's empty bed and leaves, and Su-ho sees him go but doesn't stir.
In his manor, Minister Park takes off the dragon-head bracelet he's been wearing and says, "Your Majesty, you've lived too long." He regards the dragon-head bracelet with an evil smirk.
A group of black-clad assassins jump the wall into the Hwarang grounds, where Ban-ryu meets them. He's seen Sun-woo by the pond and quietly tells them where to find him.
As Minister Park sleeps, another black-clad man picks up the dragon-head bracelet and pockets it. He takes off his mask to reveal that he's Ji-dwi, and he pulls a large knife and wakes Minister Park by aiming it at his face.
Minister Park asks who he is, and he says coolly that he's the owner of the bracelet — the faceless king. Minister Park squeaks that he thought Sun-woo was the king, and Ji-dwi corrects him: "No, it's me. I am your lord, Jinheung."
The assassins surround Sun-woo, who staggers back, unprepared. Just as the leader calls the attack, an arrow lands in his arm, and Sun-woo looks up to see Dan-se aiming his bow at the attackers while Su-ho and Yeo-wool run to his side. They toss him a sword and Su-ho draws his own, then they rush the assassins as one.
As they fight, Sun-woo and Su-ho argue over whether the others should even be there, since its Sun-woo they want. Dan-se sees Sun-woo suddenly begin to stagger, and he drops the bow and enters the fight with his own sword. Su-ho also witnesses Sun-woo looking dizzy and flailing wildly, and he rushes to his friend's side.
Su-ho re-enters the fight, and without anyone supporting him, Sun-woo falls to he ground. His eyes roll back in his head, as he succumbs to his mysterious illness.