In "Future Diary," Yukiteru Amano, an introverted middle school student, finds himself forced into a deadly competition arranged by the deity of space and time, Deus Ex Machina. The winner will inherit Deus's immense power. Among the twelve participants, including Amano, are people who regularly keep diaries, but these have transformed into "Future Diaries," each granting distinct abilities to foresee future events.
Amano's "Random Diary" appears on his phone, offering precise details about his surroundings. Though he dislikes conflict, his will to survive pushes him to team up with Yuno Gasai, a classmate and diary holder who harbors an obsessive attachment to Amano.
Throughout this harsh contest, shocking revelations emerge, drastically altering the course of this sinister game.