The story starts with a 14 year old boy, named Yukiteru Amano. He is very anti-social and spends most of his time on his phone, writing a diary. But he's not THAT alone.. Yukiteru has imaginary friends in his mind, one named Dues, who is the ruler of everything. One day, he wakes from a nap, to find that everything that will happen is written in his phone diary. Everything adds up together. Soon, he is told that he is a survival game, that there are 12 diary users, and that he has to fight them, and that the last one standing will be god, in place of Dues. They have 90 days to fight each other, before the world ends.
Yuki later runs into a strange character named Yuno Gasai, who will do anything and everything to protect Yuki. Yuno was always in the shadows, watching Yuki from afar, but when she discovers that he has a diary too, she confronts him, and never leaves his side..
