As a result of a combination of various misfortunes, Shiki ended up attending a famous delinquent school ――St. Lukimantz Academy. Shiki was a herbivore thrown into the cage of a predator called ‘Delinquents’. He himself was not the type of boy who would be bullied, and in fact, until junior high school, he had lived a life free from bullying. However, his sense of justice and more-than-slightly good-natured personality led him to be noticed by one of the many gangs of delinquents in the school. For a year after that, Shiki was bullied by the delinquents and lived a hellish life. One day, he almost collided with the strongest Yankee gal in the school, Karin Kohinata, called the [Empress] in front of a vending machine. As a result, Shiki’s school life changes drastically.