Alone in a dark room in London, a heavily wounded Cole is recording his experience with the recent
zombie apocalypse. He explains that he’s destroyed dozens of lives for N-Gen pharmaceutical company
and proceeds to share the whole story, which started two months ago. Company director Mr. White
announces RAK295, a performance-enhancing medicine that can help people deal with everyday stress.
Thirty thousand volunteers, including Angela, participate in the initial trial program, and
White assures the media that they aren’t worried about negative side effects. However a month
later, the last stage of the testing goes horribly wrong: all the volunteers experience extreme side
effects like high fever, vomiting, and internal bleeding. Cole can only watch in shock how the
test subjects scream in agonizing pain. While reviewing the subject files, the scientists
realize Angela has never returned for a check-up, meaning she may not be having the symptoms. Cole
must find her immediately since she could be the key to finding a cure. Meanwhile, Angela's husband
Joe is released from jail over lack of evidence, but his reputation’s already destroyed by the
press. His friend Steve comes to pick him up and Joe accepts to stay at his mechanic shop for now.
Back to Cole, he and his coworker Billing go to Angela’s flat, but it’s empty. The landlord comes
in when he hears them, and the duo immediately begins beating him up until he confesses Angela
left two months ago. The beating doesn’t stop, but it seems the landlord has nothing more to offer.
Hearing Billing go through all this violence makes Cole have flashbacks to all people he’s killed
while working for the company so he finally asks his partner to stop. In the meantime,
Angela is hiding with her brother Matt and her friend Kate, unaware that another company agent
is spying on them from afar. She wishes to see Joe and get the full story, but Kate and Matt
think it’s a bad idea. Afterward Matt leaves for work at the police station, where he learns about
some riots going on downtown. He also hears about a coworker has been attacked on her way here,
and now she’s fainted, but Matt leaves to see the riots. At N-Gen, Cole and Billing report
what they’ve found so far. Cole reminds White that he’s quitting at the end of the month because he
can’t do this anymore, but White just changes the subject. While discussing their next move,
they get a message from the agent that knows about Angela being at Matt's, but the recording suddenly
changes into a lot of people screaming, so they can't get the details. Afterward, they go to check
on the first test subject, who got an allergic reaction one week after receiving the initial
dose. Two days later, the subject's body and his cellular makeup changed. At that moment the
patient begins convulsing, and at the same time the power goes out, the patient gets up and begins
attacking everyone in the room with outstanding speed. As the guy jumps on any person he can grab,
the guards try to shoot him, but in the struggle the doctor gets shot instead. The patient,
now a full zombie, kills most of the crew by biting them to death. When he attacks Cole,
he responds shooting it until he runs out of bullets. For a second they think it’s over,
but suddenly the zombie wakes up and bites Cole’s hand. Cole hits him back with his gun,
but now another crew member has become a zombie too and starts another attack that knocks Cole
out. Back to Matt, he and coworker Jim are tying their boat at a dock when they see an explosion
from a nearby building. They call the station to report a request for backup, but they get no
response. Suddenly, their boss shows up and steals the boat to escape without them. The duo returns
to the station to find out what’s going on, only to discover they’re the only ones left in a
building covered in blood and bodies. The monitors reveal that the city has descended into chaos and
the zombie apocalypse is here. Meanwhile, Angela finally convinces Kate to let her leave the house,
only to come across a group of cops and paramedics trying to capture a zombie,
resulting in an officer getting bitten. The women go back inside and see the news covering the chaos
that has taken over the city. Angela gets a message from Matt, asking them to meet him at
a specific address because he got in contact with a friend that will fly them out in a helicopter,
which can only accommodate four passengers including the pilot. Moments later, Cole wakes up,
wounded but alive, and he helps the only remaining scientist trapped under a cabinet. They look right
outside the door and notice that the director has been infected as well, in fact he’s pushing at the
door trying to get in. Cole notices his own wound and the scientist gives him three injections of a
viral suppressant, which can control the infection for only eighteen hours. Then they leave the room,
only for Billing to kill the scientist because he thought he was a zombie too. Billing notices
Cole is infected and intends to kill him too, but Cole shoots him first, making him have more
flashbacks. Afterward Cole tries to leave, but his body makes him fall in pain as the virus starts
transforming him. Cole immediately injects himself and keeps going. When he reaches the first floor,
Cole finds a bunch of zombies attacking employees, so he quickly shoots them all as he makes his to
the parking lot. This area is also full of enemies that chase him among the cars, only stopping when
random drivers come by to feed on them too. These zombies are very fast and athletic, but after lots
of running, Cole manages to get a car and escape with the horde chasing after him. Meanwhile,
Angela and Kate leave in their car to meet with Matt. Cole arrives right then but he doesn’t catch
them in time, however he enters the house and finds the map they left behind together with the
car’s plate number. Back to Joe, he and Steve see on tv that a state of emergency has been declared
in the UK. Joe wants to go looking for Angela, but Steve assures him that she’s probably safer
somewhere else. On the streets, Angela and Kate get stuck in traffic because everyone is trying
to escape. At that moment, the zombies arrive at this area too and everyone begins to run away on
foot. Desperate to escape, the women hit a couple of cars with their own and get away from the jam
by driving around it, this gives Cole the chance to follow them more easily. Unfortunately a police
zombie sees Cole and jumps on top of his car, but Cole quickly shoots him in the chest. This isn’t
enough to stop him, and the zombie soon retaliates by breaking into the vehicle through the passenger
window to attack Cole, who responds by trying to choke him. The zombie refuses to die and forces
Cole to leave his car behind, stealing a taxi instead. As he leaves the city, Cole sees zombies
attacking citizens everywhere. Unfortunately a few moments later, the car runs out of gas. Now
Cole finds himself surrounded by a zombie horde, so he quickly runs toward the forest, where he
manages to hide for a while. Meanwhile Angela and Karen’s car starts malfunctioning, so they stop by
Steve’s shop and are surprised to find Joe there too. Joe's hurt by the fact Angela is giving him
the cold shoulder, and the women are frustrated to hear their car can’t be fixed. Angela comments
they have to find Matt and the helicopter, but Joe wants everyone to stay because it’s too risky
to go outside, triggering an argument. At that moment, someone begins shaking the door. Everyone
hides while Joe opens it carefully, only for Lavinia and Geoffrey to rush inside to hide. Soon
the zombie that had been chasing them breaks down the door, but Steve quickly shoots him and beats
him up for extra measure. Lavinia and Geoffrey tell them they need to leave quickly because
everyone is abandoning the city and there’s no hope for survival here, but this may be a problem
because the helicopter can’t carry them all. While the group blocks the broken door, Cole arrives at
the shop too, but he begins feeling pain again and he’s forced to get the second injection. Then Cole
makes his way inside just in time for the zombies to break in as well. Cole asks everyone to stay
hidden while he and Steve fight the zombies, starting a vicious fight that has them beating
up zombies violently until there are none left. Unfortunately during the struggle, Geoffrey gets
his hand bitten. Meanwhile, Matt and Jim wander around the station and finds zombified coworkers,
so they begin running away. The zombies follow them and manage to Jim, but the duo manages to
get out and jump on another boat and go away. The zombies don’t follow them, meaning they’re
afraid of water. Jimi asks Matt to get rid of him before it’s too late, but Matt refuses
to betray a friend. Back at the mechanic shop, Cole cuts Geoffrey’s bitten finger off to stop
the infection. Then he decides that the helicopter could do multiple trips to take everyone away. Joe
doesn’t like the idea because the pilot may not come back, and he prefers to leave in a van with
Angela instead. Cole refuses, triggering another argument. Angela steps away from their anger and
Cole goes after her to show her his company ID, telling her she’s the only one could that
can stop the outbreak. Angela's very upset by the idea of becoming a lab rat so she goes to another
room to think, soon Joe follows her to calm her down. Angela tells him about the possible cure and
confesses that she’s pregnant and that she wants to keep it, and Joe promises his fatherly support,
then the two finally reconcile. All this is overhead by Cole on the other side of the door,
making him have flashbacks to the time he had to kill a pregnant woman just because it was an
order. Afterward Cole announces they’re leaving in Steve’s van. While they get ready, Joe tells
Cole that he won’t let his wife and kid become lab rats. At that moment the zombie horde breaks in,
so Lavinia and Geoffrey take Kate hostage to get to the helicopter first. The zombies break into
the shop and Cole begins fighting them, killing them with an axe and his gun while Angela and
Joe take the van and the rest of the group runs away. When he finds himself surrounded,
Cole shoots a fuel drum filled with gas to make it explode. Unfortunately more zombies keep coming
and Cole has to escape on a bike. Meanwhile, Matt and Jim manage to arrive at the meeting location,
but Matt has to leave Jim on the boat because he is starting to turn. Then he rushes to the
helicopter, only to find blood everywhere and the cockpit empty. Matt contacts the base from
the helicopter and learns he has twelve hours to reach the evacuation side. Suddenly he’s attacked
by Jim, who has become a zombie too. Matt can’t bring himself to hurt him and runs away instead,
staying hidden until Jim goes away. While the group is looking for a new hiding place,
they’re suddenly attacked by a bunch of zombies. Geoffrey and Lavinia immediately
hide inside a building, and in the struggle Steve gets bitten. Kate begs the couple to let her in,
and while Lavinia refuses, Geoffrey feels bad and opens the door. As Kate slaps them and calls them
out for their behavior, Joe and Angela arrive too, and Joe is devastated to find his friend
dying. Soon Cole also arrives and Joe confronts him with a knife, but Cole looks at Joe in the
eyes and can tell he’d never kill anyone. Then Cole lends Joe his gun so he can give it to Steve,
saying goodbye before Steve ends things for himself to avoid the transformation. Afterward
Cole takes the group away in a van, but they barely drive for a few miles before Angela asks
Cole to stop because she’s changed her mind. Cole tries to remind her she’s humanity’s only hope,
but at that moment, another horde of zombies shows up. Cole speeds up to get away from them, but the
area is a mess of debris and the van crashes. Joe takes the chance to steal Cole’s gun before the
group leaves the vehicle, but Kate can't because she has a rod stuck in her neck. When the horde
catches up to the van, they immediately jump on her to feed. Afterward Joe aims the gun at Cole
saying Angela’s coming with him, but Kate’s death has inspired Angela and she decides to go to the
scientists after all. Then Cole knocks Joe out and carries him on his shoulders. Eventually
they reach the helicopter site and discover the pilot is gone, not to mention the blood. They
reunite with Matt and he explains the zombies are scared of water, so they could get away
on his boat. As they make their way to the river, Geoffrey’s finger infection finally begins turning
him into a zombie too. The group wants to kill him, but Lavinia takes Angela as her hostage,
asking Cole to help her husband. However Joe hits her from behind to save Angela, then Cole stays
behind to shoot her in the leg so she can’t follow them The shot is heard by the horde,
who immediately goes after the couple and feeds on them. The remaining group makes it to the
river but at that moment Jim jumps on Matt. Joe immediately pushes the zombie away and begins
fighting him, managing to knock Jim out after lots of struggle. Unfortunately Joe gets bitten too,
so he tells the siblings to leave without him. Angela says goodbye to her husband with a kiss,
then she and Matt safely leave on the boat. Afterward Cole and Joe jump back into the fight.
A horde immediately comes after them and they try their best to fight them off, but Joe is in pain
because of the transformation and is killed soon. Cole manages to push away enough zombies to hide
inside a building, bringing the story back to the beginning. He finishes his tale and decides
not to use the last injection as punishment for the chaos he helped to create. Then he grabs a
chainsaw and goes back outside to go down as a hero fighting zombies until the cure is found.