The story starts with the protagonist, Kitamikado Mikado (I did not misspell that), walking into an elaborate trap by the main heroine, Nanjou Kisa. Elaborate trap being her in the middle of undressing in the locker room with a bunch of hidden cameras set up and him walking in on her. She probably swapped out the guy’s/girl’s locker room signs to make it happen. Her goal is to blackmail him into agreeing to play a romance game with her: Whoever gets the other to confess to them or express their affection wins (and also if they get the other to wanna hump them). The loser has to become the winner’s slave for life and adhere to their whims. Why would she want that? Because the Kitamikados are something like a dynasty of leaders in Japan, destined to reign the nation. On the other hand, the Nanjous are something like an underground crime dynasty, trying to seize power from the shadows. They’re basically sworn enemies.
The next morning Mikado sits down with his parents for breakfast and gets the usual talk that he mustn’t get emotionally attached to anyone, much less a woman, so that his mind can stay clear and sharp as he’s destined for greater (kinda funny considering his mum is present too, after all). Obviously he cannot talk about his little game with Kisa, since it’s outrageous that he got caught with his pants down like that (even though practically Kisa was the one with her pants down).
Before home room starts, Kisa and Mikado have a bit of a talk, which they’ll have a lot of now and most of them boil down to trying to get the other to admit how much they’ve fallen for the other. Anyway, another side character interrupts them, Kawaraya Kokage. She’s the daughter of a paparazzi family and could’ve sworn she heard something about a locker room or other. Both Kisa and Mikado are interested in keeping their little game secret, so they deny it all, but let’s keep Kokage as a nosy character in mind.
Time to pick volunteers for all kinds of school duties. Mikado tries his luck by volunteering for library duties in hope to be able to be the only one, but little does he know since ten girls want to join them and Kisa strikes them all down (rhetorically) and now he’s stuck with Kisa on library duty. Alone for hours on end in a quiet library with the girl he mustn’t fall for.
At Kisa’s house (or mansion), she has a little talk with her grandmother, Sai, and her little sister, Mizuki. There we simply get to know why she’s doing all of this to begin with. Apparently, if Kisa can’t win this game, Sai decided that the next head of the family will be Mizuki instead. And Mizuki is kind of an idiot – or at least she pretends to be. So Kisa really wants to be the heir herself to secure the family’s future.
Time for Kisa and Mikado’s first joint library shift. Mikado went out of his way to invite some boys to come around so that there’ll be no romantic mood, but Kisa already disposed of them (rhetorically). Turns out that Kisa is, however, armed. With at least a stun gun and maybe other weapons. Mikado reminds her that she’s not allowed to hold weapons in school, but Kisa refuses to disclose what she’s got on her, so, you guessed it, it’s time for a body check! After Mikado’s stripped Kisa off all her weapons (fit for knocking Mikado out and abducting him somewhere), they discover a spider, Kisa loses it and almost blows up the vicinity with a tactical strike, but eventually he manages to just throw the spider out the window. We get a couple more scenes with Kisa trying to seduce Mikado by putting a book back real high and having him look up her skirt or that thing where the dominant partner slams their hand on the wall behind the submissive partner to cut them off their escape route (“kabedon” if you wanna google it). Then Mikado tries to fire back with some attempts of his own, in the end both their hearts are clearly shaken but obviously neither will admit their loss.
Anyway, school’s about to close and when Kisa and Mikado are trying to leave, Kokage is lying in wait for them outside the library with her camera for a scoop. Kisa would hate if Kokage interfered with their little game, so she wants to use sleeping gas to… but Mikado just grabs her by the hand and escapes with her instead – making the whole situation look a lot more suspicious than it actually is, if you ask me.
The next morning at Nanjou’s house, Kisa’s sister Mizuki takes a peek at Kisa’s phone and spots a few hundred (?) pictures of Mikado and obviously tries to press her into admitting that she’s into him, and also proclaims that she also wants a piece of him.
At school, Mikado finds that everyone’s behaving very strangely. Everyone seems to be very eager to praise Kisa and make sure he knows how cute she is – even the teachers. Mizuki comes around to talk to Mikado too and promises him to drop a hint if she can get his phone number and LINE ID.
Let’s cut right to the chase: Everyone’s weird because Mikado wasn’t driven to their usual school but to a replica where literally everyone has been replaced by actors (I shit you not) to trick him into expressing his affection. Everyone but Mikado, Kisa, Mizuki, and actually Kokage, who happened to stumble into the fake school when she was making an effort to stalk Mikado for a scoop and knocked out her doppelganger by accident. Mikado talks Kokage into using one of her weird stalking spots to get evidence of Kisa while he tries to trap her into expressing affection for him. During the whole scene Kokage eventually breaks through the ceiling, blowing the operation up, so Kisa knows she’s being tricked, and she knows Mikado knows that he’s in a fake school. This is the end of a rather big arc easily summarized in one paragraph.
On another day, Mikado, Kisa, and Mizuki are going home from school together. Kisa and Mizuki are trying to talk him into going somewhere with them, but Mikado refuses as he’s busy that afternoon.
And what is he busy with? It’s a marriage interview! Between the Kitamikados and Shizukas, with their daughter Rinka. She’s pictured as a classic Japanese beauty and basically raised to be a – or his – wife (girls only school, hobbies tea ceremony, you know the drill). On a side note, they ask what Mikado’s planning to do with Japan should he be in power and his plans sound like a (political) purge of the weak but when asked specifically replies he’d exclude their parents should they be weak, makes it a bit hard to root for the guy. But maybe he’s just telling them what they wanna hear. Anyway, their parents want them to take a stroll to get to know each other better while the grownups talk more about their marriage.
Well, they don’t seem to mesh well with each other as they don’t have a lot to talk about. Rinka states that she’s sorry she’s so boring, but she’s just so nervous as she’s dreamt of the day she’d get to meet Mikado like this. Mikado finds it hard to believe that she’d look forward to meeting the guy she’s forced to marry, so she sees right through him and asks whether he’s already got someone he likes, but doesn’t press for a straight answer – and she notices someone’s following them (apparently she’s trained for that also). He takes Rinka by the hand and runs away with her (the one hiding was probably Kokage). Rinka leaves him for a bit to freshen up, and surprise, surprise, Kisa steps out of the shadows to say hi to him. Obviously he doesn’t want the two to meet so he’s pretty desperate to somehow get rid of Kisa and she’s very much seen through him and doesn’t leave.
And then Mikado’s phone rings. In Kisa’s bag (oi). So she picks it up. Of course it’s Rinka. And of course this isn’t good. Now Rinka knows about Kisa’s existence, and Kisa really wants to meet Rinka. Mikado tries to deny that Rinka’s anyone important to begin with, but Kisa then breaks to him that she knows about his fiancee. And so it’s become unavoidable that those two meet, and they challenge each other to a feminity contest that leads pretty much nowhere. A few conversations later which further clarify that Rinka’s ready to do pretty much anything for Mikado, we get a scene where all of them eat crepes together (with the usual indirect kiss tensions), and Rinka breaks the news to Kisa that Mikado and she will exchange engagement vows (but not marry yet, I guess) in two weeks. After Kisa leaves, Rinka asks whether she’s the one Mikado’s got a crush on. He denies it, of course, but she also reminds him that he’ll have to exchange vows with her in two weeks. Mikado asks Rinka whether she’s really ok with it, but she’s pretty clear that she’s not just ok with it, she in fact wants to marry him; and she swears that she’ll make him forget about Kisa.
At home, Kisa has a talk with her little sister who’s shadowed the three of them. Kisa thinks she doesn’t stand a chance against Rinka and feels dejected. Mizuki gives her a hilarious pep talk and renews Kisa’s fighting spirit.
Rinka begins to come and greet Mikado after school so they can go home together (in order to keep Kisa from stealing him). More importantly, though, the next morning Mikado while still half asleep notices that he’s being moved and realizes that there’s a blank in his memories starting from yesterday when he went to a book store until now. When he opens his eyes, he’s on a suspension bridge, in the middle of the wilderness. Long story short, Kisa abducted him there, on top of a suspension bridge because apparently people are very emotionally moved when in life-threatening situations and can mistake that feeling for love. Also, they’re on an isolated island owned by the Nanjou family. Why? Because Kisa knows that Rinka and Mikado are supposed to exchange vows in four days. And Kisa apparently lost the emergency radio on the suspension bridge. However, there is a Nanjou mansion on the western side of the island, so they’re headed there now.
Mikado knows his Bear Grylls moves and does the hunting, gathering, and camp building for them to survive. They both get closer during the trip and through the struggles, but eventually Kisa breaks down with a fever, so Mikado has to carry her. At this point, their dialogues are basically stuffed with subtextual showings of affection for each other. Calling each other amazing, cute, Kisa asking Mikado why he’s going to this extent for her, and so on. However, the fever has hit Kisa pretty hard and she can barely cling onto her consciousness, but they finally arrive at the mansion… which is a research lab, and get detected by the intruder detection – and rescued. Even though Mikado could now still make it to the exchange of vows, he decides to stay at Kisa’s sick bed, which she obviously appreciates a lot.
The story closes with Kisa and Mikado on their way to school, obviously with Mikado annoyed and Kisa rejoiced. However, Rinka’s waiting for them and states that although the exchange of vows didn’t happen, she doesn’t mind and is set on making Mikado and herself happen. Finally, we get a short glimpse into Rinka’s private life… with her having a whole room dedicated to Mikado, much like a shrine.