Night Party is the seventh chapter in the Vampire Knight manga.
A tall man walks down the same alley where Yuki was attacked just the day before. He reaches into the ground and holds the dust in his hands. He wonders what has happened as the dust begins to blow away from him.
Kaien finishes preparing dinner for Yuki, Zero and himself. They all eat but are very quiet, upsetting Kaien. He cheers up after seeing that his "family" is actually eating. Kaien then gets serious and asks about the Yuki's injuries. Both Yuki and Zero are hesitant to answer the headmaster but he then remembers something, taking out blood tablets for Zero so that he can use them to quell his thirst. Zero is annoyed and tries to leave but Yuki stops him. Yuki then notes how the headmaster knows everything about Zero and about Zero's past, whereas she still doesn't know much. She decides to learn more about everything.
She decides to visit the Night Class and Zero accompanies her. As they start arguing about whether or not they should reveal their weapons, they are greeted by Akatsuki Kain and Hanabusa Aido. The two vampires are calm and they lead the two Guardians into the Moon Dormitory where all the other vampires are dressed up. Yuki notes how differently they look than in the daytime. Yuki and Zero are brought to Takuma Ichijo who happily informs them that they are invited to his birthday party. Takuma explains that he's eighteen years-old in vampire years and requests a kiss from Yuki, who quickly explains that she and Zero are only there to ask questions. She asks about the incident from before when he saved her from the malicious vampire. Hanabusa, who knows about the incident, says that the vampire was a Level E (ex-human vampire) and Takuma goes forward to explain the different vampire levels. Zero, being from a vampire hunter family, explains more. Yuki is surprised with all the information that she's learning, such as how Aristocrat and Pureblood vampires can control lower ones.
Kaname Kuran and Seiren arrive. Kaname says how he instructed Takuma to dispose of the Level E vampire who attacked Yuki. He asks her why she didn't say anything about it to Headmaster Cross and she says that it didn't seem important, and also because she'd like to report it herself. He sits down on a couch in the nearby room and asks Yuki to join him, which she reluctantly does. Kaname puts his hand on her shoulder and says that the safest place for her is to be beside him. Kaname and Yuki talk about the incident and Yuki says that it's all her fault, as she was being careless. Kaname then talks about how Ex-Human vampires should have never existed and goes to explain Purebloods and the vampires below them in status. He then talks about Vampire Hunters and asks Zero why he didn't kill the Ex-Human vampire at first sight, then kissing Yuki's wound, and asks Zero again if he actually sympathized with his enemy. Zero becomes angered and tries to attack Kaname but Seiren stops him. Kaname says for Seiren to ease herself, as it's his own fault anyway for provoking Zero.
Takuma and Hanabusa talk, the former noting the scary aura from the moment. Hanabusa considers wounding Zero severely but knows not to, as he claims that he doesn't want to go against Kaien's pacifist ideology. But then, he adds that he and the other vampires are only at the Academy because of their Pureblood leader, Kaname. Yuki hears this and wonders if Kaname really is a Pureblood. Takuma then reminds his guest that it's his birthday and that Yuki and Zero are still his honored guests.
The mysterious man from before meets Kaien in his office and looks at a picture of Zero, with Yuki in the background. The man is told more about Zero and Yuki, and becomes shocked upon learning that Zero was held back a year in high school. He quickly shrugs it off and understands his reason, knowing that Zero would have to meet Kaname everyday. Kaien explains that he made Zero a school Guardian. The man then says how he hasn't seen Zero in four years and is looking forward to seeing him again. He then mentions the incident with the Level E vampire to Kaien, who's indifferent to it. The man says how vampire hunters are supposed to kill vampires, as it's their nature, and Kaien tells him to be nice to Zero.
Yuki decides to leave after seeing Zero's expression. Takuma decides to cut his birthday cake and lets Senri do the honors, but Senri simply cuts Takuma's hand and starts drinking blood from it. Zero quickly leaves, overwhelmed by the blood. Yuki chases after him. The other Night Class students make note of it. Kaname tells Akatsuki that Yuki will eventually come to him. Yuki finds blood tablets on the ground while running and then sees a struggling Zero on the ground near a pool of water. She goes to him and Zero says how he's been taking blood tablets every night. Yuki wonders if it isn't helping him and notices that Zero's starting to hurt her, as his hand is on her shoulder. Zero starts licking away Yuki's neck and she realizes that he's trying to bite her. She pushes him in the water but he still goes after her. He suddenly retreats, having been shot in the shoulder, and the two surface on the water.
The man who spoke with Kaien points his gun at Zero and says how he didn't expect to kill his own student, before coldly referring to him as a vampire. Zero recognizes the man as his teacher and Yuki simply stares on.