Neka was born and raised in Shibuya, Japan. She kept to herself and ignored most other people until she stumbled upon the work of an artist known as CAT, whose murals were pretty much graffiti. She liked the murals and CAT, deciding to try and live by his motto, "Do what you want, when you want, where you want."
One day, while admiring one of his murals, a boy about her age rounded the corner with a gun. Surprised, Neka just watched as he aimed the gun at her and fired. However, he wasn't aiming for her, instead, someone behind her. Stunned, Neka fell to the ground and just stared as another person, this one a boy who looked a year or two older than she was, fired several rounds at the first, but instead of being injured, the first boy was able to stop time and dodge the bullets. The second ran off, leaving Neka to stare at the first.
She didn't stare for too long, because after the second boy left, the first leveled his gun at her and fired, killing her. He then dropped a Player Pin onto her, making her a Player in the Reaper's Game.
On her first day of the Reaper's Game, Neka woke up in Scramble Crossing with no memories of anything besides her own name. After finding the player pin, she becomes even more confused when she realizes that the pin allows her to read others thoughts. After using the pin, Neka was attacked by strange creatures, known as Noise. Unable to fight, she runs. She then gets a message on her cell phone from "The Reapers" telling her to go to 104 within sixty minutes or be erased. A timer appears on the palm of her hand, counting down from 60.
Unsure of exactly what to do, and noticing more Noise coming after her, Neka runs to the Statue of Hachiko. There she meets a girl named Misaki Shiki, who demands that she make a pact with her in order to fight the Noise. In return for making the Pact, Shiki gives Neka several pins to use in battle. After erasing the Noise, Shiki and Neka head to 104. Once there, the timer disappears, since they completed their mission.
The next thing that Neka knows, she is waking up somewhere else. She doesn't know how she fell asleep, but Shiki tells her that a day has passed and they receive a new mission, "Set the cursed statue free." Not sure what to do, Neka and Shiki try to leave the underpass that they woke up in, only to find an invisible wall blocking their way. After talking with a Support Reaper, someone that Neka is unable to scan who wears a red jacket, Shiki and Neka erase some Noise in order to clear the wall.
Once outside, they meet Beat and Rhyme, two other players in the game. They explain a few things, but leave after Neka decides to be herself and push them away. Unsure of which statue that needs to be purged, Neka and Shiki set off; only to be blocked by yet another wall. The nearby Support Reaper tells them to "Free the Cursed Statue". A short distance stands the Moyai Statue, which is surrounded by Noise.
After erasing the Noise, the wall is taken down, but the mission isn't complete. After some thinking, the two head to the Statue of Hachiko. After examining the statue and finding nothing wrong, Shiki and Neka explore for a while, scanning people to get a hint. Finally after scanning around the Moyai statue, they get a hint and go back to Hachiko and proceed to polish it. The next thing they know, they are attacked by Noise. After erasing the Noise, the days' mission is completed.
Things aren't over for the two of them yet. After completing the mission, Shiki and Neka meet Yashiro Uzuki, who tells Neka that if she erases Shiki she'll let her out of the game. Neka, thinking only about herself, attempts to do so, but blacks out before anything can happen.
Neka wakes up the next day in a dark place. After fumbling around in the darkness for a few minutes, she runs into Shiki. Neka is surprised that she's still alive, but then remembers what happened the previous night. She was interrupted by someone named Hanekoma Sanae, who tells Uzuki that a mission like that goes against the rules of The Game and she runs off.
After talking with Hanekoma, he gives Shiki and Neka a special pin that allows them to combine their abilities and perform a powerful combination attack. After talking for a few minutes about what had happened, they get their mission for the day "Erase the Master of A-East."
After finding a way out of the area they're in, Shiki figures out that they're in A-East. They had been in the darkened Concert Hall all along. With Shiki's urging, they talk to someone standing a few feet away, only to find out that he's the famous musician 777. After talking with him, they find out that his Tech is missing and offer to help find where he is.
They head south, only to encounter another wall. Shiki and Neka are told to beat some Noise in order for the wall to be taken down. After using the pin that Hanekoma gave them to erase the Noise, the two head into Dogenzka, where they find the Tech in a shop called Ramen Don. After he leaves, Shiki and Neka follow him, only to find out that he is possessed by Noise. After erasing the Noise, the Tech heads back to A-East where he finds out that the lights are broken and runs off again. Shiki and Neka follow him to Shibukyu Main Store, where they run into Beat and Rhyme again.
Beat and Rhyme tell them about 'memes' that can be implanted onto people to change the way that they think. They get the meme "blackout" on their phone and try it out on someone close by. After that they use the meme on the Tech, and he heads off again. After a bit of wandering, Shiki and Neka get several more memes and use them on the Tech, so that he gets the proper part to fix the lights.
But something went wrong, the lights aren't coming back on. Shiki and Neka figure out that they have to erase the noise that are in the concert hall. After fighting a rather tough Noise, Shiki and Neka think that they're done for the day, but the counters on their hands were still counting down. Beat and Rhyme show up and destroy a small golden bat noise before Shiki and Neka could, ending the mission.
The next day, Neka wakes up at 104, with Shiki, Beat, and Rhyme. They talk for a few minutes and then get the day's mission, "Reach Towa Records." There is no time limit this time and Beat and Rhyme decide to challenge Shiki and Neka to a race to see who gets there first. Accepting the challenge, they head off towards Towa Records.
Once they reach there, tragedy strikes. While standing and waiting for Shiki and Neka to show up, a new noise appears. In order to protect Rhyme, Beat shoves her out of the way when a shark-like noise tries to erase her.
Unable to fight, Rhyme can do nothing as Shiki and Neka erased the Noise that erased Beat. Hanekoma shows up, taking Rhyme to his café, the WildKat, where she receives a pin as she tries to deal with the loss of her partner.
The next day, Shiki and Neka wake up at Tipsy Tose Hill, where they are given the mission, "Free Spain Hill from the Noise." They figure it was simple enough and decide to run a few errands and do a bit of shopping first before heading to Spain Hill to take out the noise. After several battles, they find out that the noise aren't ending and that the source of them are two girls.
After listening to the girl's conversation, they imprint a meme on them, getting them to play a game known as Reaper Creeper. Neka slowly moves a coin around on a piece of paper and the two girls eventually solve their problems. Neka and Shiki then fight the noise possessing the girls as well as the rest in the area, completing the day's mission.
Neka and Shiki wake up on the sixth day of the Reaper's game in Scramble Crossing, with the mission of "Dominate the Scramble Crossing View at 3:00." Not sure of what to do, Neka scans a few people and figures out that they have to get people to watch an advertisement at 3:00. After getting some memes and imprinting them on a young man named Makoto at different times, they eventually get people to watch.
While doing this, Neka finds out about Shiki's entry fee to the game, her looks. After talking about it, Neka encourages Shiki to forge her own identity and continue with her life after they beat the Reaper's Game.
On the Seventh Day of the Reaper's Game, Shiki and Neka wake back up in Scramble Crossing with the simple mission of "Erase The Game Master." After searching for a while, Shiki and Neka find the Game Master, Higashizawa, and after a tough battle, they erase him, beating the Reaper's Game.
After erasing Higashizawa, Rhyme, Neka, and Shiki meet Kitaniji, who tells them that Shiki has been chosen to return to life. Rhyme chooses to join the Reapers so that she can learn how to use a Pin that she was given and hopefully find a way to bring Beat back.
The Game isn't over for Neka however, as she wakes back up in the Scramble Crossing again with all of her Pins. After figuring out that she's still in the Reaper's Game, Neka heads off in search of a partner so that she could use the pins that she has. At the Statue of Hachiko, she is attacked by Noise, but at the right time, someone forces a Pact on her and she is able to erase the noise. After the fight, she finds out that her new partner is a boy named Joshua.
After talking with Joshua about the day's mission ("X = 30 + 74"), he figures out that they have to go to 104. Once they arrive at 104, they meet the new Game Master, Minimino Sho, who makes them erase a tough noise before the day is done.
Neka wakes up on the Second Day of the Reaper's game to find out that Joshua is on his phone, talking with someone as the new mission arrives, "Acquire the √3 Au pin". Joshua figures that they have to get a golden pin somewhere. Neka, however has been thinking about what has gone on. She's back in the Reaper's Game, but now she has most of her memories back and Shiki didn't get another chance at life, she was taken as Neka's entry fee to this round of the Reaper's game.
Neka vows to get Shiki back and beat this round of the Reaper's game as they head off to find the Gold Pin. Eventually they figure out that they have to enter the Tin Pin Slamoff and win in order to get the Gold Pin. Tin Pin Slammer is a popular game among people in Shibuya, played with different Pins. Neka enters the tournament, but gets knocked out of the tournament in the semi-finals. However, another player wins, preventing them all from being erased.
On the Third Day, Neka again wakes up at the Scramble Crossing. After waiting a few minutes for the mission and not receiving one, her and Joshua head off to do some errands. They end up saving Ramen Don from a competing ramen shop, Shadow Ramen and then they go to WildKat, where Hanekoma gives Joshua a tracking program that tracks Kitaniji.
Kitaniji has his own plans, and orders Rhyme to attack Neka to prove her loyalty to the Reapers. Hesitantly, she does, but flees the fight after a short while, leaving Neka wondering what she is doing.
On the Fourth Day, no mission is given and Neka and Joshua end up helping 777 find his band's microphone by searching all over the city. Neka dubs this "The Detour from Hell." Since it was distracting them from their goal of finding Kitaniji. During this time, Rhyme attacks them again and again, she leaves before the fight is done.
Again, on the Fifth Day, no mission is given, but a different sort of Noise is out attacking Reapers and Players alike. This Noise, known as a Taboo Noise, is a lot tougher than any other Noise. Joshua and Neka head back to Hanekoma in order to get the tracking program modified before heading off to the Station Underpass. Once there, Joshua uses power that Neka's never saw before in order to erase the Taboo Noise.
Things change on the Sixth Day, they are given another mathematical equation as the mission, "Beat the bosses of 2.2360679's 0+5," and Joshua figures out that they have to beat all the Noise at the Scramble Crossing and Udagawa. Taboo Noise are still around as well, attacking Players and Reaper's alike. After a while, Joshua and Neka erase all of the noise.
On the Seventh and final day of this round of the Reaper's Game, they are given the mission of erasing the Game Master at Pork City. Upon arrival, they fight Sho, who eventually is defeated, but in a last ditch effort, he unleashes his strongest attack, and Joshua sacrifices himself in order to save Neka.
Things still aren't finished for Neka, who woke back up in Scramble Crossing for a third round of the Reaper's Game. After talking with Kitaniji, Neka is forced to play a third round of the Reaper's Game, since Kitaniji declared that her last round was illegal since her partner, Joshua, was technically still alive and not dead like the other players.
Partner less, Neka headed back to the Statue of Hachiko in order to find a partner, only to find that she was the only Player in the game! As she's attacked by Noise, Rhyme appears and makes a pact with her, allowing her to use her pins and erase the noise.
Rhyme has decided to leave the Reapers in order to help Neka, since she didn't think that it was fair that she was the only player in the game and was unable to fight. She then tells Neka about why she had joined the Reapers, in order to try and summon Beat's Noise from the pin that she was given and eventually bring him back to life.
Uzuki then summons more noise and Rhyme pulls Neka away from the fighting in order to save them both. After encountering a wall, Rhyme uses a keypin to take it down so that they could continue on. After encountering another wall that Rhyme couldn't take down, the two of them backtrack and head to 104, where they defeat more noise as the day ends.
Instead of waking back up in Shibuya on the Second Day of her Third Week of the Reaper's Game, Neka wakes up in Econtra.