The story revolves around Yukiteru Amano, a middle school student known for his reclusive personality. One day, he is unexpectedly transported into a survival game by Deus Ex Machina, the god of space and time. In this intense competition, the winner will receive unlimited power from Deus. The contestants include 12 individuals, all of whom keep diaries on a regular basis. However, their diaries have been transformed into "Future Diaries," which possess the ability to predict future events to varying degrees.
Amano has a "Random Diary" on his phone that provides accurate descriptions of his surroundings. Despite initially being hesitant to fight, Amano's desperation to survive leads him to form an alliance with Yuno Gasai, a classmate and fellow diary holder who is obsessed with him. As the game progresses, shocking revelations are uncovered, altering the nature of this twisted competition.
Mirai Nikki was published in English as Future Diary by Tokyopop with 10 volumes released from May 12, 2009 to April 12, 2011 before the publisher went defunct. VIZ Media rereleased digitally 9 of the Tokyopop volumes under the VIZ Select imprint from May 27 to December 16, 2014. The series was also published in Italian by Star Comics from December 10, 2011 to September 14, 2013; in Spanish by Ivrea España from June 15, 2012 to June 28, 2013; again in Spanish by Editorial Kamite in México from May 28, 2015 to December 29, 2016; and in Polish by Waneko from November 2014 to September 2016.