the story starts out with a little girl, yuuki, who is attacked by a vampire in the midst of a heavily snowy night. luckily, she is saved by a young bishi, also another vampire. she notes that this is where her memories actually begin.
10 years later, she is attending a school called kurosu gakuen, whose students are separated into a day class and a night class. she notes that although the afternoon separates the two classes together, many of the day class students still come to admire the beautiful night class students as they arrive from their dorms. yuuki is now one of the mob controllers (er, yeah. that’s what i’ll call them for now… although not very effective, it seems). her savior from 10 years ago is one of the night class students, kuran-senpai. popular though the night class students may be, zero, the other mob controller, isn’t really that impressed.
yuuki goes on to narrate how they’re not just public moral defenders aka mob controllers, they are actually strike guards, guardians of a large secret — that the night class students are vampires… because the vampire vs human conflict still continues from the deep past through the shadows of history. the knowledge of this shadowy history is limited only to a select few. but the vampires are all too real.
that night, zero complains to kurosu, the board chairman, how they couldn’t hold down the mob themselves (and yuuki is too useless for this job XD;; yuuki retaliates, saying that it’s zero who’s the useless slacker). but kurosu tells them that they’re the only ones he can count on.. and how his heart’s in pain because he has to lay this job on his cute son and beloved daughter (zero: “i don’t remember ever being your son!”) XD;; zero asks for yuuki’s opinion of the matter since he’s actually kurosu’s (adopted) daughter… and she just responds that everything seems fine, the night class and the day class get along… (kurosu then expresses his sparkly feelings about how he wants to eradicate the history of conflict between vampires and humans, etc.)
he later admits that there are some of the night class that might take advantage of the people, but if anybody ever found out, there’d just be too much of a commotion. (of course she vehemently responds that kaname-senpai isn’t like that at all). but leave everything to her, the guardian! and she jumps out of the window… and reflects back on how kuran kaname brought her to this man after he had rescued her…
the next day the teacher is exasperated with yuuki and zero for being asleep in class… and they all wonder why they’re always up so late (not even the teachers know about the vampires). her friend, yori-chan, jokingly suggests that they’re like vampires.. but of course those aren’t real. yuuki invites yori on the watch with them, but yori refuses, saying that she noticed how close the two were. yuuki then throws insults within his hearing.
we then find the night class in class, where they are being praised by their teacher. their newly developed tablet (pill) has been approved for use.
outside, yuuki and zero stand watch for stray day class students. zero once again questions her on her feelings towards vampires… and reveals that his interest in this assignment lies in finding a weakness with which to defeat vampires. yuuki remembers how zero first came to them: his family had been killed by bad vampires.
soon enough, however, 2 girls can be found wandering towards their location… hindered only by a cut knee. yuuki jumps off the balcony, swings herself off the tree, and lands in front of them. after some questioning, the girls try to cajole her into allowing them just a couple of pictures. she tries to hurry them away in case the scent of blood attracts night school students.
it’s too late, of course, as kaiin akatsuki and aidou hanabusa come trying to talk yuuki to put her weapon down and let them enjoy the pleasure of the blood scent. the girls are at first ecstatic having been proclaimed sweet smelling. but as they reveal that it is the scent of yuuki’s blood from her pass on the tree, the girls see the vampires’ true faces and faint.. her blood sucked, she is helpless as aidou requests more blood… through her neck.. luckily, however, zero comes to save her… which gives her a break to try and stop him from shooting them… _-_;; kaname comes down to intervene, taking the aidou in custody, and questioning kaiin for not stopping his friend. kaname adds in an apology towards yuuki, and they all go their separate ways.
later, yuuki and zero are talking. she wonders if her blood really tastes that good, since the vampire from when she was little had acted much the same way. she concludes in an upbeat manner however that she’s a guardian for the day class and the night class.
on the other hand, aidou has been suspended for the next 10 days. he wonders if the tablet would be all he has to look forward to; yuuki’s blood had tasted so good. kaname silences him.
yuuki ends with a narration about how the school had a big secret that the day class didn’t know about: the night class is full of vampires… but for now, even she doesn’t know that there’s an even bigger secret.
end for 1st night