The story begins on a cold snowy night. The young girl Yuki lost her way on a snowy moonlit night and accidentally ran into the legendary vampire - the synonym of nightmare. At the moment of life and death, one of the male protagonists, Jiu Lanshu, appears. When the vampire was about to bite, he blocked it with his arm, saved the girl, and brought her to the chairman of the Black Lord Academy, asking for the chairman's care. Ten years have passed. The little girl back then is now the first-year disciplinary committee member of the regular class at Black Lord Academy. Jiu Lanshu, who saved Yuki back then, was also the squad leader of the night department of the Black Lord Academy, and also the head of the Moon House. The regular class has classes during the day, while the night class has classes at night. The two classes take turns using the school building; the only chance for them to interact with each other is in the evening when the two classes exchange school buildings. There are reasons for this arrangement. Because the night class has an unknown secret, that is, all members of the night class are aristocratic vampires. The respected senior Jiulan is a pure-blood vampire known as the "vampire among vampires".
The vampire family all appear in the world in human form that is elegant, beautiful, and talented. As a result, these beautiful vampire teenagers have become the objects of admiration for girls in ordinary classes. And when classes alternate every evening, it is inevitable that girls will crowd in front of the school building and wait for the vampire boys. The contact between humans and vampires has inappropriate reasons. As a result, Yuki and another disciplinary committee member, Rei Tsui, took on the responsibility of guardians of the college and dealt with the troubles that occurred when human students came into contact with vampires.
Zero's family was killed by vampires four years ago, but Zero miraculously survived and was taken in and taken care of by the chairman and went to school in the academy. The unfortunate past has made Zero's character extremely cold. For senior Jiulan who saved her life, Yuki felt grateful and admired in her heart; and for Ling, who was born in a lonely life, Yuki had the care and compassion of an elder sister. On the other hand, although Jiulan has a crush on Yuki, he seems to be hesitant for some reason, not just the gap between races; while Zero also has feelings for Yuki, but his slow emotions and hard heart prevent his feelings. The story unfolds in this environment.