Carl wakes up and realizes he’s late for a game he was invited to. He quickly freshens up and heads out until he gets to a really tall building, which is the location for the game. He goes in and arrives at the meeting spot where there are also a couple of other gamers.
Shortly after, a man named Marco tells Carl and another guy who just came around named Adam that they’re late. Carl is about to explain himself when he realizes that Marco is a gamer like him, and he doesn’t owe him any explanation.
Another guy named Andre also tells them that all of them in the room are there for the game they got invited to, which none of them still have an idea of.
Just then, they hear a robot voice telling them to pick up a tablet assigned to them, and also drop off all their gadgets or valuables in a locker. After they do that, they’re all then asked to proceed to get scanned by standing on top of a machine.
With everyone scared to step on the machine, Marco goes first, and things go smoothly for him. He is then asked to proceed to pick up his equipment, which looks like body armor. After Marco, Adam goes next, and he is followed by Andre.
As they’re at the point of picking their equipment, Adam looks excited as he can’t believe he’s seeing such equipment for the first time in his life. He shares his excitement with the others, saying the game is already looking cool even without starting.
As all of them wear their body armor which also comes with a helmet, one of the gamers, Zahid, suddenly says he’s not interested in the game anymore. The others are unable to convince him, and he heads towards the entrance. However, the door doesn’t open.
While some of the gamers are wondering why the door had to be locked, Marco tells Zahid to stop delaying them. He says if Zahid knew he wasn’t interested at all, then he shouldn’t have come. With the doors locked and no way out, Zahid doesn’t have a choice.
After Zahid wears his armor, they are all instructed to drop down their visors and it appears like they’re in a virtual reality game. They appear to be soldiers in the virtual game, and they see a new place entirely, though when they take off their visors, they can see that they’re still in the same building.
As they walk around in their new immersive reality, they can’t seem to believe how real it looks. While Zahid tells Carl that he thinks they made a big mistake coming for the game, Adam continues to talk about how the game is really cool.
Suddenly, they hear a sergeant calling for their attention. They don’t know how to react, but eventually head over to meet him. Interestingly, they figure out that the sergeant is not a part of the real world, and he’s only a character in the game. The sergeant welcomes them into the game and soon takes them to a room where they’re asked to pick their guns.
He shoots the gun, and the gamers are shocked at how realistic it is, because it breaks a glass bottle. He tells them that the guns are their new best friends, and they’ll use the guns to take down terrorists in the game.
The sergeant asks all the gamers to test their guns and after they do, he tells them that their bulletproof vests will disappear if they get shot, and they need to avoid that. He shoots the vests of Adam and Marco to show the others what he means. Even though the bullet doesn’t hit them, both gamers feel intense pain that they can’t explain.
The sergeant then instructs each of them to take one stim shot. He says it’s what they can use to revive themselves if they get shot. He also mentions that without it, they’ll be in a world of pain.
After that, he informs the gamers that they’ll face different terrorists in all the levels of the game, and that the person who has the highest kills at the end of the game will win a cash prize of $100,000.
Since he has given them all the instructions needed, he asks them to begin the mission. Led by Andre, who is an ex-military officer, the group starts looking around for the terrorists. They soon encounter their first one when they’re distracted. They all avoid getting shot before Andre kills the terrorist. As they have a look at the dead body, they realize that it’s also part of the game and is not real.
They continue moving and soon come across a supply station, where some of them are able to get more ammo and also change to a longer rifle. Andre teaches them how to use it and after that, they start moving again. As they’re moving, there are a lot of terrorists in the new section and Marco gets his first kill.
With more terrorists shooting at them, the gamers run to hide and split up. Adam gets a chance to claim his first kill, but his shooting is not perfect, and the terrorist tries to kill him. However, Andre saves him and kills the terrorist, but he loses his bulletproof vest in the process.
From where they’re hiding, a girl named Taylor freaks out and complains to another girl named Shelly about how the game looks too real. Shelly says it’s not like that, but when Taylor asks her to kill a terrorist, she freezes and tells Taylor that it doesn’t look as easy as it sounds.
Just as the terrorist is about to find them, Carl kills the terrorist to claim his first kill. As Carl goes to check his kill, he is shot from behind by another terrorist. He loses his bulletproof vest, and shouts that he surrenders, but he gets shot again. Shortly after, Shelly finally builds the courage to help him kill the terrorist.
But Carl is in a lot of pain, and he’s bleeding seriously in the game. Shelly opens her visor and sees that he’s only bleeding in the game and he has no injury outside the virtual reality.
However, Carl doesn’t want to listen to that as he says he’s in a lot of pain. As Shelly doesn’t know what to do, Andre comes to Carl’s aid by injecting him with the stim shot. That is enough to get Carl to feel well again, but as he vomits, he tells the others that it’s not a game and he thought he was really going to die.
The group comes together and starts talking about Carl’s experience. Even though Adam thinks there’s probably something wrong with the calibration on Carl’s armor, Carl says they need to take off the gaming gear and find a way to leave. Just before Carl is done talking, Zahid tries to remove his helmet.
When it doesn’t work and he feels they’re trapped in the game, Zahid brings up a theory about how one of them is an insider, because he feels there’s no way the organizers would bring them together without putting someone who is an expert among them.
With this, he says he suspects Andre because he’s an ex-military officer. Andre doesn’t like this, but Marco also seems to think the same, especially because Andre was the one who taught them how to use their guns and he also led them into the first fight.
Andre says he was only acting on instincts, and he doesn’t know what they’re talking about. A fight is soon about to start, but before it escalates, Andre walks away from the group.
Just then, the robot voice announces that the level is reloading. The killed terrorists in the level get revived and they start looking for the gamers again. While Andre is trying to clear his head, one of them catches him unawares and shoots him.
Andre starts to feel the same way Carl felt, but as he’s without a stim shot, he starts dying. He shouts for help, but he is not loud enough. Shortly after, his body starts to receive shocks from the armor, and it eventually gets to his helmet, with Andre getting killed instantly.
The others also get into a battle with the other terrorists, and Adam gets the most kills in this session. Another gamer named Edward also gets shot, but he immediately uses the stim shot before his situation gets worse.
All of a sudden, they notice that they’ve not heard from Andre in a while. They go around to check and much to their surprise, they find him dead. At that point, the gamers realize that they’re dealing with something different other than just a game.
Carl asks what they’re going to do, and Edward says they need to find the organizers to shut down the game and get them out.
Before they do anything else, Zahid figures out that Andre’s helmet killed him. They all then try to take their helmets off, but it doesn’t work. As he’s bent on getting the helmet off his head, Zahid runs into another room to get a fire extinguisher. He asks someone to help him smash it on the helmet, and Carl volunteers.
As Carl smashes the helmet a couple of times, it doesn’t seem to do anything other than summon the sergeant. They all draw down their visors and see the sergeant shouting that they’re not allowed to do any damage to their equipment. Before Zahid can do anything, the sergeant kicks him repeatedly, and then warns the others not to try something like that.
As they all then look at Zahid with pity, he tells them that he doesn’t think any of them will leave the game alive.
The gamers proceed to the next level and there, the sergeant gives them knives as a new weapon because they cannot shoot due to the gas leakage in the room. As they take their knives, the gamers start moving on. Just before a terrorist can stab Edward though, Marco saves him and kills the terrorist.
Later on, they all stop at another point and Edward gets them more ammo, since they can now use their guns again. Before they can proceed, Taylor is scared of dying, but Shelly convinces her that nothing bad will happen to her, and also promises to get her out of there alive.
With that, they move on to another level where there are a lot of terrorists again. In this level, Adam gets shot, and just as Shelly is about to administer the stim shot on him, Carl also gets shot.
Shelly is suddenly confused about who to give the stim shot. However, Marco makes it an easy decision for her as he gives his own to Carl, which then allows her to help Adam.
They all move on again from there, and while they’re looking out the window with their visors up, Carl can’t help but think of trying to break the window to be able to call for help.
As he tries a few times with his rifle, Zahid takes over from him by pushing a heavy material in the room against the window. Suddenly, they hear the sergeant’s voice, and as they bring down their visors, they see him head over to beat up Zahid for trying to break the window with an equipment. In the process, he breaks one of Zahid’s legs and warns the others again.
With Zahid’s leg now broken, the group have to make a tough decision because they know he’ll slow them down. He helps them make the decision and tells them to hide him. They do that and then head over to the next level. There, Marco bullies Edward into taking a new shotgun as his weapon, after which he hands over his old rifle to Shelly, who still has a pistol.
Out of nowhere, Marco is shot and as the others try to kill the terrorist that is shooting at them, Taylor gets scared and runs to hide in a different section of the room. Shortly after, Adam is able to get the terrorist killed and Shelly also saves Marco with another stim shot. Meanwhile, another terrorist somehow figures out where Taylor is hiding. However, as he opens the door, she builds up courage and stabs him.
She then joins the others and as they take a breather, Carl asks Shelly why she didn’t have a next of kin, as he had seen on her ID form on the tablet, they were given immediately they got into the building. Shelly says she’s all by herself because she has lost her parents. Carl also says he doesn’t have anyone because his girlfriend, who used to stay with him, has died.
Just then, Carl asks everyone for their story, and he figures that all of them have no one. Adam has a grandma with Alzheimer’s, Marco is divorced and has lost custody of his child, and Edward says he’s the only child and an orphan.
Carl suddenly realizes that might’ve been picked because the organizers knew that no one would miss them. However, Shelly asks if it could mean anything because Taylor is not even a gamer, and she couldn’t explain how she got the invitation. She starts to look suspicious at Taylor, but Carl says it’s probably nothing because they don’t know about Andre and Zahid.
Elsewhere, Zahid is still in the place he’s hiding, but someone walks up to him and kills Zahid.
At the next level, the gamers see the sergeant beating up a terrorist. He tells them that there’s a bomb in the building, and only the terrorist knows the code to deactivate it. He mentions that they’ll have to torture the terrorist to get the code. Edward volunteers to do it, and Adam also chooses to be one who will type in the code after Edward gets it.
Immediately Edward starts torturing the terrorist, and the others are left surprised by how he does it without hesitation. He shocks the terrorists several times before then asking for the code.
The terrorist gives him the code, and Edward tells Adam to type it in. Adam does this, but it only happens to start a countdown for the bomb, with Marco then blaming Adam. However, Adam believes it’s a part of the game and the organizers would definitely not expect them to get the right code from the terrorist, who soon gets killed by Taylor when he starts laughing at the gamers.
Marco still believes Adam is partly at fault for typing in the wrong code, and he punches him with anger. When the others try to stop him, Marco pushes them away. However, they hear the sergeant calling for them again. When they get there, it appears that he’s holding the door to an elevator for them. The gamers all go in and hope it takes them to the ground floor.
But this doesn’t happen, as the elevator stops on the fifth floor. Marco holds the door for the others to go out, but just as he sees Adam trying to leave, he says he must go out first. This doesn’t work out for him, and he and Adam are locked back in, with the elevator taking them to the third floor.
Marco is happy about this, as it means they’re closer to the ground floor than the others. Adam tells him to let them wait for a while to see if the others can meet them, but as they get a reminder from the robot voice that they have 25 minutes left until the bomb detonates, Marco tells him there’s no time to wait.
They start moving on, but soon have to stop when Marco notices that there are terrorists ahead. He then insists that Adam leads the way and shows what he’s got. Adam is scared to do this, but he doesn’t seem to have a choice as Marco threatens him.
Adam starts to lead the way, and he’s able to kill a terrorist. In the process, he runs out of bullets, and thinks about staying behind Marco. Marco, however, continues to threaten Adam as he plans to use him as a shield.
Elsewhere, Edward starts to lead the others and after Taylor gets a new rifle, they start moving on. Before they can go too far, a terrorist throws a smoke grenade in their way. As the others try to run away from the smoke, Carl freezes at first and Shelly has to save him.
Carl starts talking about how he tried to save his girlfriend from a fire, and Shelly realizes that he went into shock as soon as he saw the smoke. She calms him, and after a while, they get going again.
Meanwhile, Adam continues to lead the way and even though he survives for a while, he soon gets shot, with Marco running away to hide. Adam soon dies and from where Marco is hiding, he hears as the other gamers kill the terrorist and also go through, but he doesn’t say a word.
They then have to face a group of terrorists and start shooting with all they’ve got. When they realize that they left the last stim shot in another room, Taylor volunteers to go and get it. They cover her well and she leaves.
Taylor retrieves the last stim shot, and is about to leave when she is blocked by Marco, who asks for it. Taylor says she’s not letting go of it, and this forces Marco to shoot her. As he watches her dying, he says she reminds him of his ex-wife who took custody of their child.
Soon after, Carl starts looking for Taylor and bumps into Marco. He is surprised to see Marco alive, and he asks if he has seen Taylor. Marco pretends like he hasn’t seen her and then tells Carl to hold on while he kills some terrorists.
Carl is suspicious of Marco, and as he checks another room, he sees Taylor already dead. However, Taylor manages to write Marco’s code name, Atlas, on the door, and this helps Carl realize that he’s responsible for her death.
Out of anger, Carl pounces on Marco and tries to strangle him. He almost succeeds, but Marco is stronger, and he breaks free. As he’s then about to pick up his gun so he can kill Carl, Marco has his helmet hit with a fire extinguisher.
Carl does this again before Marco is able to kick him away. He suddenly starts laughing, and as Marco wonders why he’s doing that, they both hear the sergeant’s voice heading their way. He yells at Marco and says that he has warned them not to try to cause any damage to their equipment.
Because that’s how the sergeant is programmed, even though Marco wasn’t the one who tried to damage it, Marco gets killed by the sergeant. With that, only Carl, Shelly, and Edward are left in the game.
They proceed to the ground floor where the bomb is, and with only a few minutes left until it detonates, they start shooting off the terrorists there. Carl suddenly gets shot, and as he’s about to use the stim shot for himself, he sees Shelly get shot too. As she’s in a lot of pain, he injects her with it, and tells her that she better makes it out alive.
Meanwhile, Edward is able to kill off the last terrorist, and also stop the bomb at the last moment, while Shelly is powerless as Carl dies.
As she’s still bothered about trying to get Carl to wake up, the sergeant shows up to congratulate the gamers. However, Shelly notices that Edward is repeating everything the sergeant is saying, and with that, she figures out that he was the inside man after all.
The simulation shuts down and Edward’s men come in to clean up. As they get closer to Shelly, she tries to shoot them, but the gun no longer works. They inject her and she passes out.
When she wakes up, she sees Edward packing all his things. He comes closer to her and gives her the prize money, but Shelly rejects it, saying that people died in the game.
Edward says it doesn’t matter, and she should be happy to have been part of something like that. Shelly says she’ll report him if she gets out of there, but Edward says no one would believe her.
She then tells him that she’d rather be dead than take the money. Edward then instructs one of his men to inject her again, but she overpowers him and stabs him with it instead.
As Edward talks about leaving the building already, so that he can plan another game, Shelly appears behind him with a gun she picked up from the guard she killed. She initially hesitates and Edward thinks he’s going to escape.
However, she pulls the trigger and kills him before walking out of the building.