Soo Baek Hyang, The King’s Daughter is one of those sageuks whose title has a lot of variants when translated into English but that and just straight Soo Baek Hyang are the ones I prefer. I typically dislike “woman’s role and status determined by relation to male” titles, but in this case the designation is extremely plot relevant, and also not something that the main character bases her view of herself on.
The series is set during the reign of Muryeong of Baekje, though with impressive liberties. I mean, it is an MBC sageuk. Historically (as I understand it), Muryeong is believed to be the son of his predecessor, Dongseong, but is made Dongseong’s cousin for VERY IMPORTANT PLOT REASONS. Muryeong is in love with Chaehwa, the daughter of Baekga, the eventual assassin of Dongseong. When Baekga is manipulated into assassinating Dongseong by a supporter of Muryeong, Marshall Hae, Muryeong brings what can only be called unholy vengeance down on Baekga. He intends to spare Chaehwa but STUFF HAPPENS and Chaehwa is saved from a fire by a servant, Kuchon, who takes her to the neighboring country of Gaya, with bother believing Muryeong intended to kill her too.
Side note on Kuchon: Kuchon is a deaf mute (Though they seem to sometimes forget the deaf part, as there are a few times he’s definitely responding to sounds.) who was a Gogoryeo assassin who was captured and converted into an agent of Baekje by Marshall Hae and sent to spy on Baekga, only to dump Marshall Hae when he falls in love with Chaehwa. He is the guy who carries unconscious pregnant women dozens and dozens of miles without breaking a sweat, gets stabbed a bunch and gets back up, grabs swords with his bare hands, and takes a twig and beats down a dozen well trained soldiers for the crime of approaching his daughter in a threatening manner. Kuchon is what happens when you merge a wuxia hero with a shounen hero after his 4th or 5th powerup.
Getting back to the plot, unknown to Muryeong, Chaehwa is pregnant and names her daughter Seolnan, but also secretly names her Soo Baek Hyang, The name she had told Muryeong she would give their daughter, if they ever had one. Eventually, she falls in love with Kuchon, and a couple years later, they have a daughter named Seolhee. Meanwhile, back in Baekje, Muryeong is wallowing in guilt because he believes he killed The One Great Love Of His Life, and because he knows his cousin was killed to make him king, which is what happens. Then he happens to be watching his three year old son, Myongnong, playing with Dongseong’s son, Jinmoo. He notices they look almost exactly alike and hatches a plot to swap the boys. Both mothers are conveniently long dead, so there’s no one to yell at him about what an incredibly terrible idea this is. The official canon reasoning given is that this way, Dongseong’s son will still be king one day, and Muryeong will never be convinced to have Jinmoo banished or killed to secure his position if Jinmoo is actually his biological son. BTW, I’m only going to refer to Myongnong and Jinmoo by the names they grew up with after this. He also latches onto the idea of having Jinmoo raised by a supporter of Dongseong’s who hates Muryeong and thinks he had Dongseong killed to get the crown and wants vengeance. I mean, surely that setup won’t lead to Jinmoo being raised to hate Muryeong and think he has to avenge his father. NO, MURYEONG, THAT ISN'T THE OBVIOUS OUTCOME. NOT AT ALL.
Anyway, that’s the official canon reasoning. The real reason is so that there can be a lot of fake-cest wallowing later on.
Moving on to the main plot (gotta love how long it takes to explain the essential back story in sageuks) Seolnan and Seolhee grow up in Gaya, blissfully ignorant if their parents’ pasts. Seolnan is perfectly content as a mountain peasant. Seolhee has a hefty dose of typical petulant "But I deserve SO MUCH MORE. I should have been born someone IMPORTANT." teen stuff going for her, which escalates quite a bit before long. Myongnong grows up superresponsible and becomes Muryeong's spy master in between crown prince duties (In another drama, Muryeong would be a cold jerk. Here, he's ruthless can can be standoffish, but is pretty much relentlessly good intentioned, and only ruthless or cold out of absolute necessity, and has few moments that comes close to jerkishness.), and Jinmoo grows up a playboy who bounces between "I HATE MURYEONG AND WILL AVENGE MY FATHER" and "I really really really want Muryeong to like me and we can bond over board games and maybe one day he'll be proud of-WAIT WHAT AM I THINKING?"
Things go bad when, on a political trip to Gaya, both Jinmoo and Marshall Hae learn that Chaehwa is living there an has a family. Marshall Hae goes to Muryeong with his tail between his legs and prepares his "So, uhm, you know twenty years ago, when I told you I'd learned Chaehwa was dead? Well, I sorta-kinda-maybe lied about that-FOR YOUR OWN GOOD-and have felt really guilty ever since. Anyway, she lives here now and has a family. Including two daughters. One of whom is probably yours. I kinda neglected to tell you she was pregnant due to the whole lying about her being dead thing." speech. Jinmoo's reaction is more along the lines of "I WILL HAVE BLOOD AND VENGEANCE. BRING HER TO ME. But don't hurt anyone. I WILL TORTURE HER AND HER CHILDREN BECAUSE HER FATHER KILLED MINE. Hey, don't hurt anyone, ok? This is, like, a peaceful, non-violent kidnapping. FOLLOWED BY VENGEANCE AND TORTURE." Jinmoo rather sucks at being a tortured-half-villainous bad boy. Too bad he's so good at causing destruction anyway, because things go TERRIBLY WRONG and people die and Chaehwa is blinded with she and her daughters are the only survivors of their village. (My personal opinion is that Jinmoo's guardian pulled his men aside and told them to be sure to murder everyone from the outset, but I have no proof.) Chaehwa dies of her wounds, but because of Plot Significant Hairpins she thinks she's alone in a cave with Seolnan and unknowingly tells Seolhee that Seolnan is Muryeong's daughter, and how to prove it to him.
Later, Seolnan is determined to find the bandits and GET VENGEANCE AND JUSTICE for their village (it's a genetic thing) and Seolhee fakes her death (except Seolnan takes the evidence she leaves behind as indicators of abduction by bandits, not death, and adds AND SAVE MY SISTER to her vengeance plans) and travels to Baekje to convince Muryeong that she's his daughter with Chaehwa.
And all this is just the setup.
Eventually, Seolnan meets Myongnong and becomes a member of Bi Mool, Baekje's secret band of spies, and they totally-do-not-fall-in-love. Except for the part where they do. Naturally, at some point, one of them learns that Seolnan, not Seolhee, is Muryeong's daughter,, resulting in a lot of "OMG NOES I AM IN LOVE WITH MY HALF-SIBLING. THE ONE GREAT LOVE OF MY LIFE IS MY SIBLING. I MUST PULL AWAY AND NOT TELL THEM WHY BECAUSE I CAN'T LET THEM SHARE IN MY AGONY." Seolhee successfully passes herself off as Muryeong's long-lost daughter and becomes increasingly involved in court politics. And maybe becomes reeeaaallllyyy close to Jinmoo, causing Muryeong to engage in some "OMG NOES, INCEST. YOU TWO CANNOT BECOME CLOSE FOR REASONS I CANNOT TELL YOU EVEN THOUGH IT WOULD BE PERFECTLY ACCEPTABLE FOR COUSINS TO GET MARRIED AND IT WOULD ACTUALLY BE A POLITICALLY SOUND MOVE BECAUSE THEN MY DETRACTORS WOULD SHUT UP BUT IT CANNOT BE BECAUSE OF INCEST THAT I CANNOT TELL YOU ABOUT."
A lot of the series is Seolnan and Seolhee involved in (and in Seolhee's case, sometimes causing) political intrigues not only in Baekje, but also in other countries. There are some filler bits, but overall, it's stuffed with plot that manages to be consistently interesting, with great characters.
Seolnan is something of a Deok Man-like character, save that she becomes a spy and investigator, as opposed to actively pursuing the throne. Her superpower is her ability to make pretty much anyone view her as a younger sister or daughter (except for her fake half-brother, who wants to marry her and make adorable but scary royal spy!babies with her), even after they learn she's betrayed them and/or used them. No, literally. Late in the series there's a scene where someone she brought down is all "I hate you and totally don't still adore you but I thought you looked kinda hungry so here's some jerky which I am totally not giving you because I know you love food and you gave me jerky that one time after I gave you sweets and...and...JUST TAKE IT I HATE YOU YOU RUINED MY LIFE!! Uhm...I hope you like it." Seolnan is genuinely sweet and awkward and has a tendency to babble and likes hew things more than food and sleep. She's also an intelligent schemer who will stick with something until she's satisfied no matter how long it takes, and if she decides your going down, you will go down, no matter what (mostly semi-ethical) means and schemes she has to employ. She and Myongnong do a lot of back and forth saving of each other over the course of the series. Myongnong is prone to bargaining and getting on his knees to beg the king to save her when the occasion calls for it. Seolnan is more likely to swear vengeance and vow to destroy you and strip you of everything you value if you go after Myongnong. And then she follows up on it. Sometimes, she also scares her nearest and dearest.
Seolhee is a bit more difficult to pin down. I'm not always sold on how they write her, and she's a very complicated character, and I'm not sure the actress was completely up for it. Mostly, I think she did a good job, but there are times when she just isn't quite able to sell it. Seolhee does a lot of horrible, unforgivable things throughout the series, though for a long time, the main thing I held against her was trying to make Seolnan think she was dead. I honestly believe that she didn't initially try to make Chaehwa think she was Seolnan in the cave, but that she was in so much shock (she had just killed a man in self-defense, and she and Seolnan were separated in the attack on their home, and had different experiences through it) that she could speak until Chaehwa realized which daughter she was speaking to and snapped her out of it. After that, I think the trauma made her cling to the fantasy of being the king's daughter that she used it to escape from the reality of her past and herself, and couldn't let anything intrude on the new reality she created for herself. Which doesn't excuse anything she did (was is a lot of awful stuff throughout the series) but in the end, I mostly find her pitiful.
You know that trope in fiction, where there are two men or two women and they're either family, or incredibly close friends, and one goes down the bad path and the good one swears that that's it, they're over and will be ENEMIES FOREVER? And if it's two women, that really is it, and you'll never get another scene of them not being enemies, and they probably don't interact much after that, but if they're men, then they just CAN'T end it there, and the bad one is always tormented about the need to destroy and the good one knows they don't deserve another chance, but just can't make themselves cut the bad one off, no matter how much they say they will and no matter how incredibly bad things get, and that relationship is the main propellant for the drama and conflict?
Well, Myongnang and Jinmoo never reach that point (Ok, Jinmoo thinks they do, but we've already discussed how badly Jinmoo fails at effective villainy. He's even worse at it when it comes to supposedly hating Myongnong, or thinking he doesn't care about Seolhee and acting like he's ok using her to hurt Muryeong.) but Seolnan and Seolhee are there, and it's amazing. It's also frustrating, because as much as I loved that Seolnan could never completely give up on Seolhee, even when she thought she had, there were times when I really wish she had for her own good. But as much as she wants to, she can never stop viewing Seolhee as her sister first. Seolhee, for her part, plots against Seolnan in her need to maintain her fantasy world, and even when she's trying to hurt Seolnan or not wanting Seolnan anywhere near her, part of her always wants Seolnan to come back and love her again.
Other importrant characters I didn't mention yet:
Chancellor Yon: Jinmoo's guardian, who I did mention, but who gets an extra, special mention for his terrible childrearing skills.
Jinmoo's bodyguard: Whose name I forgot. He is very loyal and appears to be a rather decent person, and so I have no idea how he ended up with his job.
Eun Hye: Marshall Hae's daughter, and Baekje's current queen. Muryeong sees her more as a daughter than a wife, but she has other opinions on the matter. She is initally very much not suited to palace life, but grows a lot over the course of the series. She and Seolnan are pretty much eternal BFFs.
Dae Woon: The head of Bi Moon, who is decidedly Not Pleased with Marshall Hae's tendency to sacrifice his people.
Kang Bok: Myongnong's body guard and another member of Bi Moon. He is very long suffering and secretly ships Myongnong and Seolnan a lot.
Na Eun: Seolhee's maid, who is a little too intelligent and observant for Seolhee's good, and has a Secret Role.
Dorim: Dorim is the historical Buddhist monk sent by Gogoryeo to manipulate Muryeong's father, king Gaero, and is responsible for weakening Baekje's defenses and causing Baekje to lose land to Gogoryeo. In this version, Dorim was actually a teenaged girl (but still a buddhist monk) who later defected to Baekje, and is devoted to helping Muryeong reclaim the lands she made his father lose. In the meantime, she's in charge of the palace flowers, and for turning female members of Bi Moon into superspies. She's very good at it.
Ttol Dae and Mang Goo: Bandits from Gaya who knew Kuchon, and later come to Baekje with Seolnan. For the most part, they make for very good bandit sidekicks/surrogate family, but I really dislike how the show ignores how they first met Seolnan. She and Seolhee were lost after Seolhee went to a part of the mountain they weren't allowed to go to. Ttol Dae and Mang Goo find them, and taunt the with rape. There's no actual rape attempt and even before they were reformed, rape seems to be pretty out of character for them, so I'm willing to believe that it was an intimidation tactic that they had no intention of following up on, but I really dislike how the show and Seolnan herself seem to completely forget about that. (I do want to mention, though, that to the best of my recollection, this is the only time there was even a suggestion of rape.)
Mak Geum: Chaehwa's maid who tells Marshall Hae about Chaehwa's pregnancy, and that she saw Kuchon carry Chaehwa out of the fire (thinking that he'll tell Muryeong, who will then look for Chaehwa.) Marshall Hae tells her Chaehwa is dead and gives her money to disappear. She knows he's probably lying, but also that he'll kill her if she questions him, so she takes the money and uses it to build a merchant empire and rescue other runaway slaves, and spends the next 20 years looking for Chaehwa.
Kko Mak: An innkeeper who takes in Seolnan and Seolhee after they lose their home (her inn is conveniently placed on a crossroads between Gaya and Baekje, the perfect place for Seolnan to carry out investigations FOR HER REVENGE). She also goes to Baekje with Seolnan because Myongnong really really likes her cooking, and because she and Ttol Dae really really like each other.
Adorable little orphan boy: An adorable little orphan boy who pretty much forces Kuchon to adopt him while Kuchon is on his own vengeance quest. He doesn't have a name until the last two episodes.
I eyed the series when it was airing but was leery about the "enemy sisters" aspect, and then one day I looked and saw there were about 90 episodes and went "Nuh uh." Later I learned that it was a daily drama that was 108 episodes. Unlike most dramas, which air 2 60-70 minute episodes on two consecutive nights, daily dramas air half-hour episodes Monday-Friday. There are even fewer sageuks among daily dramas than in your average kdrama percentages. Like their hour-long countparts, daily drama sageuks are more expensive and difficult than contemporary-set dramas, but with less exposure and typically lower ratings, making it harder to get big-name actors, which sageuks often rely on, and they also have to film more scenes per week because they have to have an extra half-hour of scenes per week. I actually only know of one other sageuk that's a daily drama.
I actually find 108 half-hour episodes less daunting than 54 hour long episodes. It's a lot easier to sit down and know you have time to finish an episode when it's short episodes. That's just me, though. The different format is that it also allows for different narrative structures. An obvious one being that, if needed, an episode can focus exclusively on one character or plot, without actually losing momentum or distracting form all the other plots going on. For, example, Seolnan barely features in the episode where Seolhee first presents herself to Muryeong, but features heavily in all the episodes around it, so the show was able to exclusively focus on that one important plotpoint without losing focus or momentum for everything else for the week. Later on, there's an episode that's almost entirely two family members who thought the other dead for two years barely missing each other the whole episode, to be finally reunited in the last couple minutes. Normally, that'd have to be split between other plotlines in the episode because a series couldn't devote half its airtime that week to it, but here they can comfortably fit it in while still keeping everything else going for the week as a whole. Airing 5 consecutive days and never having more than 2 days between episodes also means that the series could do cliffhangers and storyarc climaxes in ways that other dramas can't do. Certain cliffhangers are just fine for a 24-hour wait, but not a 5 day wait, so they could end on a rising BAM moment anytime they wanted without worrying about viewer frustration.
There are some things that rely on irritating contrivances, like the toddler-swapping (MURYEONG THAT WAS SUCH A TERRIBLE IDEA DESTINED TO BACKFIRE ON YOU) and times when characters are clearly not knowing about something or being kept out of something purely because ever so much could be cleared up by their seeing something or hearing a description, but the overall drama and plot and characters are great enough that I could usually roll my eyes and move on. I think I watched this in the space of about 3 1/2 weeks, if that.
Hulu has it but, sadly, neither Netflix nor DramaFever do. It is very, very worth watching, though, and everyone should hunt it down and watch it so we can talk about it.