We start with a grizzly murder.

Cut from there to school. Yukiteru Amano, our MC calls himself an observer. He doesn't participate in things, but obsessively keeps track of everything that happens on a diary in his cell phone.

He has no real friends, but rather, imaginary ones.

Like Deus Ex Machina, God of space and time. And Murmur, his servant.

Deus asks if he wants to change his life, and sends him a message that contains the future. This will be a new game.

Meanwhile, the serial killer continues to stalk people who are out alone after dark.

When he wakes the next day, Amano sees that his diary has already been entered. With surprisingly confirmable details.

Deus tells him that the diary is his future, with that drawback: if it is destroyed, he will die.

Yuno Gasai, one of Amano's classmates, catches his eye. She's left behind a clay figure of Murmur.

How can she see what's only in his head?

Worse, his diary says he'll be caught and killed on the way home. Dead End.

Gasai knows this, because she also has a Future Diary. And she's been stalking Amano and writing his movements.

But that does mean she can help him avoid Third, the other diary user and serial killer who is after him right now.

They lure Third to the roof of the building, and when he draws his phone to check where they are, Amano punctures it with a thrown dart, killing him.

Deus brings the eleven remaining competitors into a vision and explains the rules: They must discover and kill each other.

He names Amanao, First. No doubt the top contender if he could pull off a miracle like that.

It was actually Gasai's doing, but Amano has the target on his head.

Don't worry, Gasai will protect him, with all the force that a Yandere girlfriend can muster. (Worry.)

The winner of the contest will get Deus' cosmic powers!

By the way, Third was the homeroom teacher.

The Ninth keeper, Uryuu Minene, comes to the school to follow up. She has placed remote detonating bombs around the school to flush out Amano.

The head cop tracking her, Fourth, is also a Future Diary user.

Ninth protects her phone by putting her eye in harms' way instead. She escapes.

Fourth is not interested in godhood, but wants to stop the murders. He proposes a team-up between himself, Amano, and Gasai.

Each person's diary shows different details based on how they write.

Fourth's name is Kurusu Keigo.

(Gasai is Second.)

Amano and Gasai go to an amusement park together... to lure out the other Diary keepers. Yeah, that's it.

Ninth escapes, but is captured by another Diary keeper.

Amano opens a locked door at Gasai's house and is shocked.

Why does she have dead bodies (mummies?) in her spare room?

Amano flees, but it's not like he can really get away. She knows everything he does, after all.

His opening of this door changes everyone's future.

Ninth has been captured by a cult. The leader is Sixth, Kasugano Tsubaki.

She has a Dead End showing in her diary. She wants to trade Ninth for Amano's help avoiding it. He's dodged two already.

The problem is that Sixth's diary shows what her cult does...

... and they've been hypnotised by Twelfth. Information about the future is worthless if it's false.

Gasai figures it out, but also believes Sixth is poisoning Amano against her.

She give him an ultimatum: come with me and live, or stay with Sixth and die.

Obviously, because the bad guys are after Sixth. This isn't her threat.

Twelfth, Hirasaka Yomotsu, is insane. He thinks he is a super hero.

Gasai dispatches him.

But it's a double cross! With Twelfth gone, the cult is un-hypnotised, and Sixth turns on them.

Gasai pushes Amano out of harms way, but Sixth orders her cultists to gang-rape her while broadcasting it over the loudspeaker to draw him back out.

Even though Gasai is crazy, Amano won't stand for this, and he kills Sixth by darting her diary.

The official report is that the deaths are from a mass suicide at the cult.

Gasai breaks in to cook dinner for the whole family. Amano's Mom likes her.

One of Mom's coworkers was in the cult and died. She'll be looking after their son for a few days.

The son is a diary user.

Fifth, Houjou Reisuke, begins his campaign of revenge against Amano and Gasai.

Amano tries to find his diary. Gasai takes a more direct route.

When he unleashes poison gas, Gasai becomes as interested in the antidote as the victory.

Luckily, stabbing gets her both.

Tenth asks Deus if he can transfer his diary. What is his plan?

Amano and Gasai transfer to a new school. Amano makes fast friends with Hinata.

She suggests they should totally check out the site of a gruesome murder!

It is a trap. She knows about the diaries.

Hinata is Tenth's daughter and has his diary. She takes Amano's diary at knifepoint.

Aru Akise, another classmate, fakes having a diary and engages Hinata in a high stakes bet. Can he beat future information? Yes. Lying to Amano puts false information in the diary.

Gasai has Hinata at knifepoint. She's far more concerned that she will steal Amano than about the current situation.

Amano makes her back down with the only thing he has to offer: officially acknowledging her as his girlfriend.

Fourth finds Tenth and kills him.

We get a flashback of Ninth's backstory.

Akise sets Amano and Gasai up on a date. Would Amano fall for Gasai if he didn't know about the bodies?

Akise snoops around. But Gasai has disposed of the bodies.

Fourth sets Amano and Gasai up to take the fall for Tenth's murder.

Fourth "interrogates" Amano by playing Russian roulette. Gasai steals an officer's gun and breaks him out. They go on the lam.

While hiding, they meet up with Ninth, who explains: Fourth's son is dying and now he wants to win.

They all have Dead Ends in their diaries now.

Fourth comes for them, but Ninth arranges things so the other cops see what he's up to and arrest him. His diary shows what happens on his cases, so it's useless now.

He asks Ninth for one final favor, and pays with his life, destroying his own diary.

Amano and Gasai disappear.

Detective Nishijima inherits Fourth's case files. He learns about the diary holders.

He and Akise work out a plan to have their high school friends search for them, figuring they'll run if the police do the search.

They all get captured.

Gasai has gone a whole new level of cuckoo bananas. She has taken over an old hotel and has Amano prisoner, as well as all the others.

But Kousaka (Amano's friend) suddenly gets upgraded to an Apprentice Diary Keeper. He busts everyone out.

How? Eighth has the ability to share.

Eighth's diary is a server: anyone who runs a blog on it gets the effect. She sends some of her users to take out Amano.

The defense plan is: if they cut cell service to the area, Eighth's Child Diaries will stop working, and they can take them out.

But it's a fakeout.

The people who have actually come are not Child Diary users, but Seventh: Ai and Mar are lovers whose paired Love Diaries tell them how to protect each other. (They are both Seventh.)

They see this as a lover's duel: which couple's love is strongest?

It's Seventh.

Seventh take Amano and Gasai's diaries and send everyone to the hospital.

Ninth arrives to train Amano for a plan to beat Seventh. This is fake, but if Amano believes it, Seventh will read it in his diary and be fooled.

Amano's father arrives. He has been suborned by Eleventh.

Seventh draws them into a trap, but Gasai recognizes it and recovers their diaries. Eighth's agent destroys the building.

Amano's dad steals Seventh's parachute to escape. Amano's mom confronts him and he kills her.

Seventh die. Amano and Gasai escape with the other parachute.

I'm sure you've all been wondering: did Gasai kill her own parents?

The answer is yes, but by the time that's confirmed you realize that there's a reason she's crazy and it's their fault.

--

Eleventh's agents kill Amano's father. Amano decides to win so he can fix everything.

Amano plays hardball.

He unmasks Eleventh, revealed to be the Mayor. He allies with Eighth to take out Eleventh, then double crosses her.

But right as their victory seems assured, Akise and Ninth arrive. They found three bodies buried under Gasai's house: her parents, and her.

This Gasai is an impostor.

Amano doesn't care.

--

Eleventh hooks up Eighth's diary to a supercomputer and gives everyone in the city an account: his plan is to be the leader of a clairvoyant kingdom.

Nishijima rescues Ninth from Eleventh's men and proposes to her!

Amano's friends team up with Ninth to take out Eleventh's supercomputers.

Eleventh's diary, The Watcher, shows him what everyone else's diaries say.

In fact, Eleventh was the one to suggest Future Dairies as a part of the death game in the first place.

Ninth figures it out.

By editing false information into their diaries, they can fool Eleventh.

But he's one step ahead. His secretary has a diary that records his actions. That one is known to be reliable.

Ninth loses a hand in an explosion. Nishijima is shot dead. Amano's friends are captured.

This is when Amano and Gasai swoop in, armed with submachine guns, to rescue Ninth and move on to the next phase of the plan.

Eleventh seals himself in a bank vault.

When they can't open the door, Ninth turns on Amano, aiming to get revenge for her eye, and for Nishijima.

Bad news: Deus Ex Machina is a load-bearing God. As he reaches the end of his life, reality starts to break down.

Akise breaches the gates of heaven to confront Deus. But Deus says that he isn't even real - he's an Observation Terminal for Deus to keep tabs on the diary keepers.

But Akise disagrees. Observers may only observe, but he's used Eighth's power to give himself a Future Diary, and he intends to use it to save Amano.

--

Akise and Amano's friends betray him and help Eighth escape. Akise fights Gasai to a standstill.