Plot: Yuki Cross's earliest memory is of a snowy night in winter, when she was attacked by one vampire and was saved by another, Kaname Kuran. Yuki is the adopted daughter of the Headmaster of Cross Academy, Kaien Cross, who is an ex-vampire hunter that now wishes for vampires and humans to live alongside peacefully. She has grown up and become a prefect for the school with one main purpose: for vampires to coexist peacefully with humans. Her fellow guardian, Zero Kiryu, a childhood companion whose parents were killed by a pure-blood vampire, is now determined to kill them all and refuses to trust them. Zero himself is now manifesting vampire traits, having been turned into vampire after he was bitten by a pure-blood vampire, Shizuka Hio, four years before.
Yuki tries to help him fight his bloodlust while also seeking to recover the memories she lost. As the series progresses, Zero's thirst for blood leads to his drinking from Yuki, by her consent, to avoid becoming a level E vampire. To stop this, Kaname gives Zero his own blood, making him a normal vampire which will prevent Zero from going insane and from needing to feed from Yuki. Eventually, it is revealed that Yuki is a pureblood vampire herself, the sister and fiancee of Kaname. To save Yuki from being killed by Rido Kuran, Kaname's uncle, her mother had sealed her memories shortly before her own death. After Yuki reawakens to her vampire nature, Rido again tries to kill her. As Kaname kills the vampire senate, Yuki fights Rido. During a fierce battle, Zero aids her in killing him, but later on tells her he will have to kill her one day.
(source Wikipedia)