The numbered doors appear in Nine Hours, Nine Persons, Nine Doors. In the Nonary Game, these doors each carry a red number from 1 to 9. The goal of the survivors is to seek a door with the number 9 on it.
They function with digital roots, as players must add numbers to create a digital root that equals the door the players want to go through by placing the correct bracelets on the RED. Only 3 to 5 players may go through a numbered door. The doors remain open for nine seconds, which then activate the bracelets of those who went inside. They will have eighty-one seconds to deactivate their bracelets via the DEAD or the bombs will explode. Only those who scanned their bracelets on the RED can scan their bracelets on the DEAD.
Nine Hours, Nine Persons, Nine Doors
The numbered doors are first seen when the players of the Nonary Game meet each other and go to the B Deck. There, they're faced with Door 4 and Door 5. Santa says that the exit from the cell he woke up in had a numbered door as well. Everyone else says they did as well and begin talking. Eventually, a few people, most notably the bulky Seven, attempt to use brute force to get the doors open, but fail to succeed.
Zero, talking over a speaker, interrupts after their attempts die down and tells the players to read the rules of the Nonary Game. They learn that each of them have a paper that explains the game, and learn about the goal of the Nonary Game and the function of numbered doors and bracelets. Zero wraps up the introduction and leaves the participants to their own devices. The players decide to investigate what they can, but turn up nothing. From there, they decide to pick code names to call each other. It mostly goes well, up until Clover asks the person with the number 9 bracelet what he wants to be called. He states that it's unneeded, because he isn't going to go with the other players. He then holds Clover at knife point and forces her to scan on Door 5's RED. He forces Ace to scan as well and does himself. With the numbers 4, 1, and 9 in the RED, he opens the door, ditches Clover, enters the door, and waves the players goodbye.
The door closes and the players begin to recuperate. They also try to open the door back up, but fail. However, they hear beeping while doing this, and decide to listen in on what was going on. They then hear the man who entered (who Junpei nicknames as "the 9th Man") screaming about how he was lied to. He bangs on the doors and begs the others to open it, but the RED refuses to accept any numbers and simply reads "ENGAGED" to any input attempts. The 9th Man attempts to say who lied to him but blows up before he can. The RED then switches to "VACANT". The players re-open the door and are faced with the gruesome sight of the 9th Man's corpse.
- "The dark, reddish-black pool of blood... The scattered pieces of flesh... Organs strewn across the floor like the blossoming of a grotesque flower... The explosion that had torn through his body had been powerful."
- — Junpei, remembering the 9th Man's corpse.
The players remain shocked for a while and only decide to move when they realize they have only 8 hours left to escape. Lotus refuses, saying she doesn't want to end up like the 9th Man, but Santa counters by supposing the 9th Man had triggered a trap. Snake then begins laughing and says that the 9th Man only died because he broke one of the game's rules. He then reveals a paper he was given that explains how to use the REDs and DEADs and elaborates further on the bracelets. He reads it out loud, since it was Braille and thus illegible to everyone else.
The players discuss their options some more, among other things. They eventually decide to go through the numbered doors as a half hour of talking passes, leaving them with only 7 and a half hours. However, Lotus and Santa refuse to go through Door 5. Seven and Snake offer to go instead, and Clover, not wanting to be separated from her brother, declares she's going as well. Since they only need the number 1 to open Door 5, Ace volunteers to go with them. This leaves Junpei, June, Santa, and Lotus to take Door 4.
If Junpei agrees to go through Door 4, then the participants remain in this formation. The group going in Door 5 head in first, and are listened in on by the Door 5 group. When they hear that the Door 4 group made it safely through, they head through their Door and end up at the Second Class Cabin.
However, if Junpei insists on taking Door 5, then the formations change. The Door 5 group becomes Junpei, Snake, and Seven. The Door 4 group becomes Clover, Ace, Santa, June, and Lotus. The Door 5 group head through the door, deactivate their bracelets, shared what happened with the Door 4 group, and then headed into the First Class Cabin.
Large Hospital Room
Upon arriving at the Large Hospital Room, the remaining eight survivors are faced with three numbered doors: Door 3, Door 7, and Door 8. However, they find out that the doors don't work. The REDs have some of their parts missing. They split up to search for the RED components, investigating the many rooms in a nearby hallway.
As the players search, Zero repairs the REDs and kidnaps Snake, placing him in a coffin in the chapel. He then places a drugged Nagisa Nijisaki in Snake's clothes near the hospital room. Later when Door 3 is opened, they find the remains of "Snake" in the Shower room.
At 1 AM, everyone to the hospital room, only to Snake is missing. They search for him but yield nothing. With nothing left to do, they choose to open the doors. An argument begins when they realize that the bracelet numbers they have make it incompatible for everyone to go through a numbered door. Lotus proposes someone sacrifice themselves, much to June's distaste. Ace decides to sacrifice himself since the other numbers would work out nicely. Although June objects, he injects himself with Soporil, leaving her unable to stop him.
They then realize that in order to continue, three of them must take Door 7, and the other three must take Door 8. Seven and Lotus don't want to be together, so they choose to take Door 7 and 8 respectively.
If Junpei chooses to go through Door 7, he goes with Seven and Clover to the Operating Room while Lotus goes with Santa and June through Door 8. If Junpei chooses Door 8, he goes with Lotus and Clover to the Laboratory, and Seven goes with Santa and June through Door 7. If Junpei picks Door 3, Santa says they can't. Junpei refuses to accept this, so he tricks June and Seven into verifying their bracelets under the guise of them all escaping. Junpei then explains that either Santa or Clover and Lotus can join them to make the correct digital root. Lotus and Clover try to run to the RED, but Santa is faster and makes it there first. They then all go to the Shower Room.
In the Safe Ending, after Clover is killed and Junpei retrieves a note from the safe, he realises who the killer is. He brings the other five remaining players to the Large hospital room. He has Ace, Lotus and Seven scan their bracelets on Door 3 via their palms, Junpei then waves his bracelet over the RED, and beeps with Junpei able to open the door. Junpei reveals you don't need to place your hands on the scanner panel to activate the RED but merely using the bracelet works as well.
Junpei then asks Ace who he is. Ace says he's Junpei, but Junpei says he is Santa claiming they swapped clothes. He asks Ace why he thinks Junpei is Junpei and he says because if he was Santa, Door 3 wouldn't open. Junpei capitalises on this, calling it strange, and reveals Ace has Prosopagnosia, which he reluctantly admits.
Junpei states that he believes Ace is the killer, and tells him there are three pieces of evidence that support this, the first, Junpei says that Ace used Soporil on himself on purpose, to prevent the others from goign through Door 3, which would reveal the death of "Snake", Ace denies this stating he was just acting altruistically. Junpei argues that he knew that the doors would lead back here, but Ace denies this has well.
Junpei then reveals his second piece of evidence, believes that the killer has prosopagnosia. As he killed Nagisa, who Junpei calls Guy X, who was wearing Snake's clothes, he states that someone who could differentiate human faces wouldn't make the mistake Ace did. He reveals that Clover told him Snake had a prosthetic left arm, when you could see the bone of the left arm in the shower room. Ace states that he has no motives, Junpei says he has two motives. The first being that Snake knew about Ace's past and the second being that Snake had a grudge against Ace, due to the First Nonary Game, and that he might strike back. Santa asks what the grudge was and Junpei shows him the paper he got from the safe. He reads part of it which says that the person with the number 2 bracelet played before and that it was organised by Gentarou Hongou. Ace says he was being framed, and Junpei uses this to his advantage, saying Ace's real name is Gentarou Hongou. Ace admits he is Gentarou Hongou, CEO of Cradle Pharmaceutical, but denies knowing anything about the Nonary Game.
Ace asks how he could have killed Guy X, saying he could do it on his own, but Junpei says he could of and puts his hands in his pockets saying he took something of Ace while he was unconscious. On instinct Ace puts his hands in his pockets, and Junpei smiles, his trap working and reveals Ace has the number 9 bracelet. He explains that he could have used his own bracelet along with Guy X's and the 9th Man's to open Door 3.
Ace then laughs, admits he is the killer and that he took the knife and Bracelet 9 from the First Class Cabin and then killed Guy X and that he is also the killer of Clover, as Ace was worried Clover found something in Door 1 and that Snake might have told Clover something. He admits to being defeated by Zero but not by Junpei. Lotus then punches Ace, who grabs her and puts a gun to her face, which he obtained from Door 6. He then admits to being the killer of the 9th Man, by tricking him into believing the DEAD's had been modified and going into Door 5. He explains his motives, being that the 9th Man knew Ace, to obtain the Number 9 bracelet as it is an important number, and that he wanted to see if the Nonary Game was a joke or not. He then leaves for Door 9.
In the Safe Ending, Ace confessed to killing four people and took Lotus hostage at gunpoint, dragging her down to the chapel. They take the small Door 9 and opens it using the Number 1, 8 and 9 bracelet. They make their way through the Library and Study. Meanwhile, Junpei and Seven pursue, but they get to the chapel too late to stop Ace from going in to the door. Seven and Junpei think about what they are going to do next, and suddenly, they hear a pounding noise from the coffin.
First, they try to open it by force, but to no avail. They find a keypad on the side of the coffin and realize that it is electronically locked. Junpei looks around for clues, and Seven mentions that he remembered him mumbling some numbers back at the 1st class cabin. He then goes on to mention the "sinister hand" tip, saying that the numbers came from it. Seven suggests that the combination for the coffin might be the same as the one for the safe, as Zero had set them both up. Junpei is doubtful, but Seven pushes him to try it, saying that it won't hurt. He reluctantly inputs the numbers, and to his surprise, it opens.
The lid slides off and Snake sits up in the coffin. They rejoice at finding each other, and Snake tells the two how he had gotten trapped in the coffin. Afterwards, they explain what's been going on with the rest of the group, only ommitting Clover's death. Junpei takes a look at Snake's bracelet and mentions that the three of them can't make a digital root of 9. Seven cuts in and reveals that he had found the 0 bracelet in the Captain's Quarters. He goes over to the RED and makes sure that it functions. Seven pulls the lever, only for the screen to say "ERROR". They wonder what is going on, and Snake suggests that the value of the bracelet is not actually zero. They decide to experiment to find out the true value of the bracelet, and they find that it has a value of six. The ship freaks and Snake says they should get moving. Seven addresses the fact that he can't come with them, but Snake says that he had a plan. Seven and Junpei authenticate, along with the 0 bracelet, and Snake crushes his prosthetic arm and slides his bracelet off. The three men rush through the big Door 9.
In the True Ending, the players discover the existence of another Door , Junpei realized that Zero had deceived them well from the very beginning. Seeing as someone had to be left behind due to the digital roots combinations, Seven offered to stay behind, but the rest of the players decided that there had to be another way for all of them to escape.
Santa decided to solve the problem by using the gun he had stolen from the cargo room and use June as a hostage. He shoots at the floor to show he is serious, while Clover berates him, saying she thought he was one of us, something Santa refutes. He forces Ace and Lotus to accompany him and June and leaves Junpei, Clover, and Seven behind.
After they left, Junpei saw the digital root for their bracelets only add up to 7 and they needed a bracelet that displayed the number two. As they were stuck in their dilemma, a coffin placed ominously in the chapel started to make a noise and the only way to investigate what was the cause of the noise was to open the coffin itself. However, the coffin could only be opened after an 8-number combination was inserted. After opening the coffin, Junpei discovers Snake inside.
After Clover hugs Snake, Junpei and Seven explain their situation, with the dead bodies in the Shower Room and Captain's Quarter's, which Seven was surprised to learn as Junpei did not tell him due to everything else that was happening. Snake was curious as to why they were dead. He states he was grabbed while they were searching for the dead. Junpei wonders why Zero dressed Guy X in Snake's clothes or why he pushed the buttons. Snake says they should leave since they have less than an hour, since he has the Number 2 bracelet.
Junpei asks them to wait before leaving wanting to figure things out, they open Door 9 normally, but go in. Seven says that was obvious but Junpei wonders what happens if they add Zero's bracelet, which Clover has.
Junpei explains to Seven that they found the bracelet on the dead body in the Captain's Quarters, who he calls "Cap", they state that they should be able to open the door with just Clover, Junpei and the number 0 bracelet. However an error comes up, Seven says that maybe the bracelet needs to be on the wrist but Junpei disputes that saying it just needs to be over the scanner panel.
Snake says that the bracelet must not be a 0, but something else, after experimenting they realise it was a 6. The others are confused but Junpei realises it is a letter O, Clover asks if there are two people with number 6 bracelets, Snake thinks there isn't and makes an educated guess that June's bracelet was never 6 to begin with but rather a 9. Clover asks if the numbered bracelets were a lie.
Snake asks why she thinks that, an Clover draws a diagram, saying that if June's bracelet was 9, they wouldn't get through. But Snake notices Santa went through every door with June, they realize that Santa's bracelet is 0, as that is the only combination that allows them to go through. They deduce that Santa is Zero and that he was still playing by the rules. Junpei isn't sure since there would be two number 9 bracelets. Snake decides that they should all enter the smaller Door 9.
Later on, Junpei, Seven, Snake, and Clover all find their way to the incinerator. When inside, they find June next to the wall unconscious while Santa was struggling on the floor. Meanwhile, they also find that Ace has taken the gun from Santa and that he is holding Lotus hostage in front of Door q, as he only needs her to escape, due to the fact he has the Ninth Man's bracelet. Despite Ace's efforts, the RED wasn't responding.
During Ace's struggle with the RED, Seven decided to sieze the moment and tackled Ace, freeing Lotus. Meanwhile, Santa reveals that he was Zero's assistant and that Zero is Akane, and that the game's purpose was to save her. Santa takes back the gun, but this time takes Ace hostage and leaves the incinerator. Just as he does this, Akane disappears.
After Santa leaves, the incinerator suddenly turns on, and the remaining players try to escape. Lotus suggests that the others leave her, as that is the only way how they would be able to create a digital root of 9. The others refuse to leave her behind, but try to see if the door would respond to their bracelets anyways. However, the RED still didn't respond to their bracelets. Afterwards, a sudoku machine appears in the room, and Junpei decides to play it, as it is their only chance of escaping the incinerator.
After he is finished playing sudoku, Junpei figures out that there isn't a 9 on the door, but a large lowercase q. As the digital root of the letter q is 8, all five of the remaining players were able to escape, including Lotus. Eventually they reach the sit of the facility and realize that they were in Building Q all along, and that there were not any detonators inside their bracelets. The five then find a car, and chase after Akane and Aoi. During their chase they encounter a hitchhiker named Alice, and decide to give her a ride.
Virtue's Last Reward
- Main article: Number Nine Door