Yukino Miyazawa is the female representative for her class and the most popular girl among the freshmen at her high school. Good at both academics and sports on top of being elegant and sociable, she has been an object of admiration all her life. However, in reality, she is an incredibly vain person who toils relentlessly to maintain her good grades, athleticism, and graceful appearance. She wants nothing more than to be the center of attention and praise—which is why she cannot stand Soichiro Arima, the male representative for her class and the only person more perfect than her. Since the first day of high school, she has struggled to steal the spotlight from her new rival but to no avail. At last, on the midterm exams, Yukino gets the top score and beats Soichiro. But, to her surprise, he congratulates her on her achievement, leading her to question her deceptive lifestyle. When Soichiro confesses his love to Yukino, she turns him down and gloats about it at home with only a hint of regret. But the very next day, Soichiro visits Yukino house to bring her a CD and sees her uninhibited self in action; now equipped with the truth, he blackmails her into completing his student council duties. Coerced into spending time with Soichiro, Yukino learns that she is not the only one hiding secrets. [Written by MAL Rewrite]

"Unwritten" - An episode about Futaba and Kou in middle school. Based on the chapter called "Unwritten." also known as chapter 0 or Prologue. "Page.13" - An episode that continues the story after the television series's 12th and final episode. (Source: sakisaka10)

Imagine this: you are living a normal day in your life. Maybe you are out with friends, eating your family's home-cooked meal or spending time with your girlfriend. When you next wake up, you are suddenly thrust into a strange, new world, surrounded by five strangers on a rapidly sinking boat in the middle of a storm. For Natsu Iwashimizu, this is her new reality. Humanity has perished, and all that remains of the Japanese population are five groups of men and women who were chosen to be sent to the future in hopes of continuing mankind's existence. While every other person chosen has a useful talent such as martial arts, knowledge, or architecture, Natsu is a shy high school girl who cannot even raise her voice to shout. The new world is dangerous beyond imagination, and although Natsu seems to lack helpful skills, she must go with the others making their way to the "Seven Fuji" in order to survive. [Written by MAL Rewrite]

Aine Yuuki, who is a regular student at Star Harmony Academy's normal division, meets Mio Minato from the idol division, who invites her to join Aikatsu to fulfill Aine's goal to make friends. She also befriends Maika Chōno and Ema Hinata who are also idols. Aine and Mio form a pair to become best friends to become the bright "Diamond Friends". Karen Kamishiro and Mirai Asuku are categorized as "Diamond Friends" and are in the Diamond Class! (Source: Wikipedia)