Advanced placement into a school of higher grade proof-reading is determined by the results of the Promotion Test strictly for class type. Ranging from A class with the best facilities anyone can offer all the way down to F Class which is composed of low dining tables, rotten tatami mats and other worn out facilities. Students can change classes by competing using the Examination Summons Battle system or ESB. Students summon characters with their equivalent test mark scores and use them to compete with other classes.
Thirty years ago a strange phenomenon called a "spacequake" devastated the center of Eurasia, claiming the lives of at least 150 million people. Since then, smaller spacequakes plague the world on an irregular basis. Shido Itsuka, a seemingly ordinary high schooler comes across a mysterious girl at the ground zero of a spacequake and learns from his sister Kotori she is one of the "Spirits" who are the real cause of the spacequakes that occur when they manifest themselves in the world. He also learns that Kotori is the commander of the airship Fraxinus, crewed by the organization Ratatoskr, and is recruited to make use of his mysterious ability to seal the Spirits' powers thus stopping them from being a threat to mankind. However, there is a catch: to seal a Spirit's power, he must make her fall in love with him and kiss him.
Senō Natsuru is your normal, everyday high school student. However, he's been chosen to be a Kämpfer, who's objective consists on fighting other Kämpfer with either guns, swords or magic. However, there's catch—first, you can't chose if you're a Kämpfer or not, and second, you must have the body of a girl to use your powers.
The story centers around Kanade Amakusa, a boy cursed with the mental power of "absolute multiple-choice" — a multiple-choice quiz will suddenly appear in his mind, and the choice he makes will become his reality. For example, he would have to choose between going nude from the waist up or the waist down in school. While in school, he is given another choice: 1) A beautiful girl will fall before him or 2) he will fall from the rooftop in female clothes. He chooses option 1, and a blonde girl named Chocolat falls before him.
Kazuya Maeda is a high school student who has received a digital camera from his father. Motivated by this new hobby, he enters the school´s photography club. This gives him the opportunity to see several new perspectives towards the girls near him.
Yukiteru (Yuki) Amano is a loner who never really interacts with people and prefers writing a diary on his cell phone, with his only companion being an imaginary friend named Deus Ex Machina, the God of Time and Space. However, Yuki soon learns that Deus is not a figment of his imagination but real when Deus makes him a participant in a battle royale with eleven others. Within this "Diary Game", the contestants are given special diaries that can predict the future, with each diary having unique features that gives it both advantages and disadvantages.