A short OVA that was bundled with the limited edition of the eleventh volume of the manga.

Yukiteru Amano is a loner who spends his time writing in his mobile diary and talking to an imaginary friend, Deus Ex Machina. However, one morning, he finds his diary entry for the day has been filled in already. Stranger yet, the events portrayed in the diary start coming true. Deus, who reveals he is an actual God, warns Yukiteru that if he loses his diary, he will die. As Yukiteru starts using the diary to his advantage, he is approached by a stalker named Yuno Gasai who also possesses a Future Diary that foretold his death at the hands of a serial killer, another Future Diary owner. Helping him evade the killer, Yuno helps Yukiteru throw a dart into the killer's phone, killing him. Afterwards, Deus explains the rules of the survival game to Yukiteru and the other diary owners, in which they must try to kill each other in order to win the right to succeed him.

After some hesitation at seeing the innocence of her other self, Yuno lunges at her, but she is stopped by her other self's parents. Meanwhile, the actions of Yuki and Uryu have caused a domino effect that has changed the future of almost every diary holder for the better. When Balks reads about his other self's death in Yuki's diary using his incomplete Watcher Diary, he calls off his partnership with Deus, who decides to cancel the survival game and find another method to determine his successor. Yuki manages to remember Yuno and break free from the illusionary world, in the process releasing his world's Murmur, who had been trapped by her first world self in order to impersonate her. Faced with Yuki's love and her other self's united family, Yuno's resolve to kill them all is lost, and she decides to commit suicide. A horrified Yuki is declared winner of the survival game by his world's Murmur and spirited away through a vortex. 10,000 years on, Yuki is still grieving Yuno's death in his now empty universe, refusing to create anything. At the end of the episode, the final entry in his diary changes from "Yuno died" to "Yuno came to see me", and her voice is heard calling his name.

Yuno Gasai lives a normal life as a first-year in high school. She gets along well with her parents and even has a small circle of friends. However, she cannot help but feel as if someone is missing from her life, someone so important to her that it was as if she had lived another life trying desperately to stay with them. After a class trip to the beach, Yuno returns home; but in the middle of the night, she receives strange messages from a voice only she can hear. The voice informs her of the person she is desperate to meet and that she must find him. Soon, she finds herself in a mysterious realm, her only goal being reunited with the person she cannot remember. Though obstacles stand in her way, Yuno will stop at nothing to meet her beloved once again.