The cover from the first issue of Future Diary: Mosaic
Future Diary: Mosaic is a spin-off manga of the Future Diary series. It features Minene Uryu as the main characters and focuses on her endeavours before and after she acquired her Diary. This manga is canon to the original series.
Summary
Future Diary: Mosaic is about a few days prior to the original events and is mostly about Minene Uryuu and how she met the other diary owners. It is also about how she got her future diary and what made her make the decisions she made in the original events.
In the first manga Minene is shown to be granted her future diary by Muru Muru while she was on a terrorist mission assasinating a holy person.
In the second manga Minene is shown together with 12th but the chain of events is slightly altered.
In the third manga Minene meets 5th, it is shown that 5th was preparing for the attack later in the events on Yuki and Yuno. Minene takes his dolls away and teases him, however, when Reisuke runs away, Minene regrets her act and wants to return these dolls to him. Minene secretly helps him in gathering all the stuff he needs, however despite all her efforts Reisuke doesn't want to take back the dolls she took from him. This 'helping' goes even that far that Keigo Kurusu, whom she had formed an alliance with, is forced to hold back the police investigation about all the sudden Minene-like appearances throughout Sakurami City. In the end Reisuke is shown visiting his deceased parents in a body bag and he goes to sleep next to the body bags with Minene wishing him a peaceful sleep.
In the fourth manga Minene's confrontation with 3th is shown partly and her reunion with Masumi Nishijima.
In the fifth and last manga Minene meets Akise Aru, who helps her despite knowing who she really is. Minene takes off to participate in a miss contest in Sakurami City during a festival. The other participants are Hinata Hino, Ai Mikami, Ueshita Kamado, Yuki's mother Rea Amano, Mao Nonosaka and Miyashiro Orin. Instead of who is the most pretty, the contest is about throwing darts, solving a puzzle and arm wrestling. Minene wins the contests by cheating her way out, but she flees before she can receive her prize. Akise goes to the starving Minene and brings her food that the shop owners sent her for brightening the festival and the contest.