In California in 2017, Val loves to play a first-person shooter called “Field of Fire”. She’s very good at it and her nickname “Speedrun” is famous in gaming circles. Her dream is to win a tournament and become a professional.
One morning her father Carlos reminds her that he called in a favor to get her a job interview with his brother, pointing out how important this is because she hasn’t had a job for months. He asks her to pick up her grandmother from the doctor’s when she’s done, and Val reluctantly agrees. Val leaves the house in nice clothes for her interview, but this is a trick.
Her boyfriend Evan is waiting for her outside and Val changes into casual clothes as soon as gets in his car. Evan thinks Val shouldn’t be skipping an interview to go to a videogame tournament, but Val says she’ll just call in sick. The prize is ten thousand dollars, so if she wins she can finally go pro.
Unfortunately Evan has bad news: the best player in the community will also be participating. When they make it to the arena, everyone is already going crazy over Roy also known as Killohertz. He’s been people’s choice Gamer of the Year and appeared on magazine covers.
Even the commentators are sure he’ll win. Val is desperate to defeat him, but Evan reminds her she’s not here to win, she’s here to qualify. The game begins and Evan is the only one cheering for Val.
She’s the first player to get a kill and get points on the board, but Roy suddenly appears from across the map and starts stealing her kills. Sometimes he stops playing just to high-five his fans and even covers his eyes while playing just to show off. Val doesn’t give up and continues to give her best until she and Roy are tied.
With only a few seconds left on the clock, Val has an opponent in front of her and has the chance to kill them to win, however she sees Roy nearby and starts chasing him to get a glory kill. To her shock, Roy’s character disappears from the screen and reappears behind hers to kill her, winning the tournament. On her way out Val keeps ranting about Roy, not understanding how he could pull off movements that are faster than human reaction.
Evan tries to bring the mood up by pointing out she’s made it to finals, but Val thinks it’s useless if she can’t beat Roy. Speaking of Roy, he approaches Val and mocks her for a few minutes before leaving to take selfies with his fans. While Evan goes to get the car, Val is approached by Kojima, who congratulates her on her playing today but points out she’ll lose tomorrow.
He claims to be a “fairy grandmother” and gives her his card, saying that if she wants to win she’ll need his help. Kojima also confirms that Val was right about Roy: nobody can humanly be that good. When Val gets home, Carlos asks about the interview and she pretends it was fine, but he talked to his brother and knows she didn’t even show up.
She didn’t pick up her grandmother either, and Carlos almost lost his job because he had to do it himself. He announces Val will have the interview tomorrow so she tries to tell him about the finals, which are her dream and also could bring good money. However Carlos says this isn’t about money, it’s about Val lying to him and only thinking about herself.
This makes Val snap, saying that she doesn’t want a crappy life or job like his and that she understands why her mother left. Afterward Val opens a job application on her computer but ends up switching it to a gaming stream. Worried about Roy, she takes Kojima’s card and decides to visit the address.
She finds a place called “the Gold Saucer”, which turns out to be a gaming café. Kojima doesn’t even say hi, he just makes her sit and play. Val picks a bullet hell game at its highest difficulty, so she loses in seconds.
Then Kojima tells her to take a sip of “Impulse 9”, which Val thinks it’s an energy drink. When he opens the bottle, the fizzing sound makes everyone in the room turn to look at him. Kojima promises it’s a normal drunk and pours it into the cap for her.
When Val drinks it, she feels her brain completely changing: her senses are heightened and her reaction time reaches an incredible speed. Now she can beat the hard game without losing a single life. Moments later Val snaps out of the effects and finds herself at a table with Kojima, who explains that Impulse 9 stretches time.
The harder it’s stretched the harder it snaps back, and Val was out for an hour. He can sell her a bottle of Impulse 9 for $500 but that’s all the money Val has left, not to mention it would be cheating. Kojima points out that Roy doesn’t think it’s wrong and takes his call to sell him more Impulse.
After seeing all the high scores she achieved with just a sip, she decides to buy it. The next day, Val takes a sip of Impulse 9 before the tournament starts. Time slows down for her as the game begins and she can kill opponents without breaking a sweat.
Unfortunately Roy keeps drinking Impulse 9 and soon catches up to her, quickly passing her by a few points. Soon the effects of Impulse 9 end for Val, who is so desperate to win that she ends up drinking the whole bottle. With her fastest reflexes yet, Val kills Roy’s character and wins the tournament.
The effects of so much Impulse 9 last much longer and Val wakes up to find herself in the year 2029 A. I. , which means “after impulse”.
She’s living in an old dirty house with three children who call her “mommy”, and the shock makes her throw up. When her husband Evan tries checking on her, she runs outside and discovers this is a post-apocalyptic future with people living on the streets and using chemical toilets. Evan runs after her to give her a gas mask before reminding the kids that it’s time to study.
While the couple takes the kids to school, Evan reminds Val of their chores: they take turns scavenging the wastelands and being on gate duty. One of the children picks up dried dog poop thinking it’s a neat rock and asks Val to save it so she can have it back after class. “School” turns out to be a teacher with a few tables in the middle of the street.
The teacher teaches the kids that if they see a “death lizard” they must run and hide. Val wants to talk to Evan about this strange situation but she’s interrupted by a neighbor calling her “sheriff”. The woman explains another neighbor snapped back from Impulse last night and doesn’t remember the last eight years of his life.
Deputy Dan drags that man out of his tent and calls him a “pulser”, causing Evan to insult the guy. It turns out “pulsers” are people who drank too much Impulse and became useless, which caused the apocalypse. The president was also a pulser and snapped back with his finger on the nuke button.
Evan wants to beat the guy up but Dan stops him and asks Val for orders since the guy has no useful skills. Still confused, Val tells Dan to kick the man out. Afterward Evan wants to know what Val wanted to talk about, but Val doesn’t want to be kicked out so she pretends she just has a stomachache.
Evan reveals that they ate beetles last night while Dan pushes the pulser out of town and closes the gate. At that moment the weather alarm goes off and everyone puts on their gas masks. Later at home Val is freaking out because she doesn’t know what to do with a baby.
She thinks of calling her father for help, but he’s already dead and his ashes are in an urn nearby. Val reminds herself she’s a strong champion to put herself together before she’s called by Dan, who reminds her it’s time for latrine duty. Apparently in this future Val is a sheriff, a sanitation commissioner, a scavenger, and a mom all at the same time.
Val spends the rest of the day cleaning toilets, which leaves her very tired. But when she goes home she can’t rest because she must take care of the kids while Evan is on gate duty. Days pass with the same routine and Val is tired of it.
Sometimes she gets gate duty too, which means staring at nothing for hours. There’s also doing the laundry, peddling a bicycle to recharge the generator, and eating terrible food. The kids try connecting with her and even gift her a drawing of her, but she’s cold and aloof.
One night Val comes home to discover “Field of Fire” on TV. It turns out that Evan peddles a bicycle to power up the game console for a game night once a month. Instead of sleeping before her next shift, Val shows her kids what an amazing player she is and even teaches them how to play, which allows her to finally bond with them.
A few hours later, Val is still playing with the kids because she forgot to take over her gate shift. Evan shows up to inform her nobody was there to open the gate for Dan and he’s been killed by a death lizard. Dan’s wife yells at Val before Evan reminds her it’s still her shift, so now Val has to stand at the gate and deal with her guilt.
In the morning Val tells Evan she can’t do this anymore. If they work all day and taking a break punishes them, then she doesn’t see the point of living. Evan offers comforting words, saying that she’s been the most amazing wife and mother, not to mention responsible, so she shouldn’t let one mistake put her down.
This isn’t enough for Val, so she waits for Evan to leave before packing a few things and writing a goodbye letter. Evan wakes up to find his wife gone and reads the letter to discover she was a pulser. She apologizes and agrees that pulsers have no place in civilized society, that’s why she’s left.
Meanwhile Val walks through the wastelands and finds the bodies of other pulsers. After wandering for hours under the scorching sun she’s shocked to find The Gold Saucer, which isn’t as shiny and new as it used to be. However Kojima is still inside looking exactly the same as twelve years ago and keeps the store running thanks to solar panels.
Val yells at him for ruining her life, so Kojima tells her he can’t do refunds but he can do store credit. He pulls out a huge bottle of Impulse 9, saying she can drink the whole bottle and stay in the store playing videos until she dies, which is a better life than she has now. Val takes the offer and sits down to play, but at that moment she remembers her daughter’s drawing and notices it says “my hero” in the corner.
As she thinks about all the things her family has told her, Val decides to go back to town. Later at the gate Evan won’t open the door for Val and tells her to go away, thinking she only came back because the wastelands are even worse than town life. Val slides the drawing under the gate and explains that she wants to be the person her kids think she is.
She promises to do all the chores, take double shifts, and do whatever it takes to make it work. However it’s hard for Evan because she doesn’t remember the last twelve years of their life together. The moment is interrupted when they hear gunfire in the distance.
Evan yells that the death lizards are coming and the alarms go off, so Val takes the chance to slip in while Evan goes to find their kids. Everyone in town is panicking and packing the essentials to hide in the ravine because they have nobody to protect them: their deputy is dead and their sheriff is an Impulse junkie. If they don’t run, the lizards will kill them.
Not wanting to lose her home, Val joins her family and tells them to hide while she does her job. Then Val goes to the gate and gets a few things ready like fuel barrels and the big bottle of Impulse 9. The lizards arrive in a truck and Val is surprised to see Roy is their leader.
He recognizes her too and mocks her as he describes how his gang will eat her and her family. Suddenly Val throws the Impulse bottle and Roy realizes she’s drunk it all. The gang gets ready to attack, but Val is now much faster and shoots the barrels to create a big explosion.
She shoots a gangster as he flies by while another one dies of his own grenade. Val continues shooting to kill a few more guys, but a stray bullet from the enemy hits her shoulder and makes her fall. She still manages to shoot down the last gangster, only to bring her hand down when Roy shoots back.
He gets ready to deliver the killing shot, however Val dodges it and shoots him in return, finally killing him. Afterward Val shoots a flare to alert the others that the town is safe. Val then dies with her daughter’s drawing in her hand.
