The film begins with a man named Sam who is at a party hosted by a woman who used to be his ex-girlfriend. Sam's purpose in attending the party is not to have fun, but rather to retrieve his belongings, which have been the house. However, Sam's ex-girlfriend tells him to wait for a while because there are a lot of guests at the party.
After a long period of waiting, Sam begins to lose his patience due to the fact that his ex-girlfriend never returns. He again asks where his belongings are so that he can take them on his own. His ex-girlfriend eventually tells him that the items are in a nearby room.
She also tells Sam to wait there so that they can talk privately about their problems. Sam then goes to the room that his ex-girlfriend had mentioned, and he starts to look for his belongings. Since Sam can't find the items, he locks the door so that no one else can get in.
After he manages to find his belongings, blood suddenly comes out of his nose, forcing him to take a rest for a while. While Sam is sleeping, we can hear a scream from outside of the room. The next day, when Sam has just woken up, he intends to return to his house with his belongings.
But when he comes out of the room, he is shocked by the fact that the entire place is a complete mess. In addition, there is bloods splatter all over the place. Sam tries to check outside of the room, but he discovers that people, including his own ex-girlfriend, have turned into zombies.
After witnessing all of these horrific events, Sam tries to maintain his composure and begins to consider how he will survive the zombie attack. He can hear a strange noise from the floor below, and he is startled by a gunshot, which shatter the floor of his room. Sam tries to check it and it turns out that the gunshot was fired by someone who had shot himself.
He breaks through the floor and goes down to find out what is really going on there. Sam then realizes that this man committed suicide after shooting his own wife who has turned into a zombie. He immediately takes all the food supplies along with the person’s weapon.
After that, he goes out to close all the doors to ensure that no more zombies would enter the building. Sam starts doing some preparations, before he begins to inspect each and every room in the building. While collecting useful items, he marks which rooms can be used and which rooms have been occupied by zombies.
When Sam has finished checking out all of the rooms, he plans to return to his room via the elevator. But there's already an old man who has turned into a zombie in the elevator. Sam decides not to kill the zombie because he believes the zombie is not particularly aggressive, and instead ties the iron fence with a belt.
Later that night, Sam decides to calm down by listening to his recordings. The following day, he starts to observe the movements of the zombies that have taken over the area. He then calculates the amount of food supplies he will need to survive during this zombie invasion.
After he finished counting the foods, he let out all of the emotions that are building up inside him by blasting music as loud as he possibly can. But he doesn't realizes that it will actually attract the zombies. Sam starts to wonder if there are other survivors in the city, as it appears that the city has now become very quiet, like a dead city.
After a few days have passed, Sam spends his time entertaining himself by playing music, exercising, and shooting zombies, and other activities. Without any friends or someone still alive, he could die of boredom and despair that haunt his mind. After that, he is about to throw away the corpse that is downstairs because the stench starts coming into his room.
However, because Sam can't bear to throw the corpse away, so he keeps the grandparents' bodies in a room and seals the hole in the door so that no more stench escapes. When Sam is cleaning himself, the water unexpectedly runs out, forcing him to find another way to fulfill his water needs. Later that night, while Sam is sleeping, he is startled awake when the zombies outside manage to break through the door and bite him immediately.
Well, it turns out to be just a nightmare that Sam has had numerous times. The following morning, he tries to calm himself down by exercising while listening to music. Aside from that, he has frequent conversations with a zombie grandfather, whom he refers to as Alfred.
When it comes to water needs, Sam tries to collect a variety of items that he can use to to collect water when it rains. When Sam is practicing shooting, he sees a cat passing by, and he immediately goes downstairs to get the cat. The cat initially tries to approach Sam when he tries to feed it, But the cat suddenly runs away, prompting Sam to chase it.
When Sam goes looking for it, some of the zombies in the area begin to chase him away. He then runs straight into the building and shuts the door immediately. Sam is very disappointed because he fails to find the only friend who could accompany him when he is alone.
He has been injured in the leg as a result of the runaway incident. Fearing that he would turn into a zombie, he takes his gun and points it at his own head. After waiting for a while, Sam is relieved to realize that the wound is nothing more than a minor scratch, and he breaks out laughing.
The next day, Sam notices that the zombies are no longer in his area. He has no idea where they've disappeared. He tries to observe from the top of the building, but he can't find any humans or zombies around.
Since the weather is getting cold, Sam goes back into the house to take a hot bath to warm up his body. It appears that Sam is starting to feel lonely because he is left alone in the city. He plans to leave from there, but he is too scared at this point so he gives up his plan.
He expresses his emotions by scolding the zombie Alfred. Sam then starts to play his drums so loudly that the zombies who had previously been missing are now begin to come over to him. This hopeless boring life slowly makes Sam start to lose control of his own mind.
In that state of emptiness, he no longer knows how to console himself. In the middle of the night, he wakes up to the sound of something outside, and tries to shoot the door. When Sam approaches it, he realizes that it is not a zombie, but someone who has survived the zombie attack.
Sam then takes the woman into the house and attempts to save her, since this is the first time he has met someone who is not infected. The next day, Sam is happy when he sees that the woman is still ALIVE. The woman named Sarah, and she says that she has survived by moving from one building to another.
It turns out that there are still a lot of people who have managed to survive in the same way as Sam. However, the majority of them have suffered from stress, and some have even gone completely insane. Sam tells Sarah about his daily routine and the things he does.
Furthermore, he introduces Sarah to the zombie Alfred. Sarah gives Sam a a little warning because they don't know when Alfred's zombies will attack them. Sam appears to have changed dramatically as a result of Sarah's presence in the room.
When he is surrounded by other people, he begins to feel what life is all about. As usual, Sam tells zombie Alfred everything he's thinking. On the following day, Sam decides to share his food supply with Sarah.
However, because the food supply is limited, he plans to go into one of the rooms that were previously occupied by several zombies. He punches a hole in the door and shoots all the zombies inside. Sam takes all the food supplies and other items he could possibly need from the room.
When Sam returns, he becomes panic when he can't find Sarah. It turns out that Sarah has already on the roof of the building. Sarah tells Sam that she intends to leave the building as soon as possible because it is impossible for them to stay in the building for an extended period of time.
They will never know if there are people out there who have survived and built a safe shelter for them. Therefore, Sarah prefers to go there rather than having to wait in this house without any certainty about the future. Sam tries to convince Sarah to stay with him, since he is actually too scared to do so.
Sarah then claims that if Sam doesn't leave, he'll become delusional and end up taking his own life. Sam tries to apologize to Sarah for saying something hurtful earlier. In the end, it turns out that everything he had experienced with Sarah was a hallucination.
It was later discovered that Sarah had never woken up since the incident that night because she had actually died. Sam is very sad when he has to accept the reality. After conducting a funeral for Sarah, Sam goes through her belongings in her bag.
He then found out that Sarah has been married. But it seems that Sarah's entire family has died from the zombie outbreak, with only Sarah remaining alive. After that, he decides to take Sarah's advice, and burns all of the recordings he had been using to entertain himself.
Just as he is about to leave, he remembers that he needs to get zombie Alfred out of the elevator. It seems zombie Alfred doesn't want to bite Sam, and he simply walks away. However, Sam is startled by the sound of a fire alarm, which caused by a smoke from the recording he had previously burned.
As a result, the zombies on outside are drawn in, and they are able to break into the building. When Sam notices this, he tries to fight the zombies, but due to the large number of zombies, he enters and locks himself in an elevator where Alfred was previously staying, He also tries to climb up the elevator to go upstairs. But one of the zombies manages to catch up with him, forcing him to fight the zombie.
Sam then climbed in through the hole he had made before. It turns out that there are already several zombies lurking behind the smoke. It seems that the zombies doesn't realised Sam’s presence because of the thick smoke.
Before the film ends, Sam immediately rushes out of the bulding, and throws the rope he had prepared in the first place. When he notices one of the zombies approaching him, he immediately jumps and crashes into the building next to him, knocking him out cold and unconscious. Soon after, Sam finally regains consciousness, and starts climbing the rope.
Sam now has to make his way through all of the buildings in the area to get to the next place. And with that, the film ends.
