Tsukune Aono, an average teenager, is unable to get into any local high schools due to his poor grades. His parents enroll him in a private school called Yokai Academy, which he discovers is a boarding school for monsters. The school teaches monsters how to coexist with humans, including disguising as them, but any real humans found on campus are to be killed. Although he fears for his life, Tsukune befriends a beautiful vampire girl named Moka Akashiya, who enjoys his company and especially the taste of his blood. During a fight with a school bully, Tsukune accidentally removes the rosariofrom Moka's necklace, and discovers that she transforms into a powerful vampire with a completely different personality. Because of Moka, Tsukune decides to stay at Yokai. He befriends formerly antagonistic students, including a succubus Kurumu Kurono and a child prodigy witch Yukari Sendo. They join the school's Newspaper Club and wind up fighting a variety of students and teachers, who use their monstrous powers to bully or to control one or more of the members for their own selfish or destructive ends. On a club trip to the human world, they meet witch Ruby Tojo, who defends a field of sunflowers from being torn down by developers. They meet Mizore Shirayuki, asnow fairy student who becomes Tsukune's "stalker". A group of "Monstrels" harass the club, causing Moka to transfuse blood into Tsukune to the point where he turns into aghoul. Ruby, having recovered from injuries, joins the school's staff as the Headmaster's assistant. An evil group called the Anti-Schoolers threaten to break down the barrier between the human and monster worlds. When Tsukune's cousin manages to sneak onto the school grounds, the club has a hard time keeping the monster school a secret. When the school is temporary closed because of damage, Tsukune returns home to the human world only to have Moka, Kurumu, Yukari, and Mizore follow him and hide in his room.