The film revolves around a video game live streamer’s struggle for survival as he is forced to stay alone at his apartment in Seoul during a zombie apocalypse. It was released in South Korea on June 24, 2020, and globally via Netflix on September 8, 2020.

Oh Joon-woo is alone in his family’s apartment when zombies begin to attack and infect people outside. When he inspects the apartment hallway, a neighbor barges in. He begs to stay, but becomes a zombie and attacks Joon-woo. Joon-woo pushes him out and locks the door, then watches a large zombie attack his neighbour through the peephole. Joon-woo then receives messages from his parents telling him they are safe.  Joon-woo blocks his front door with the fridge and posts a rescue request on social media. By attaching his phone to a drone, he scouts his neighborhood and realizes it is now overrun. Though the emergency power stays on, Joon-woo gradually loses access to phone networks, the internet, and running water.

One night, Joon-woo sees zombies taking down a police officer outside. He screams at them, leading a zombie to break into the apartment and knock over the fridge, destroying the food. Joon-woo lures it into falling off the balcony. He resorts to drinking liquor to survive, but hallucinates about his family due to hunger and thirst. When the phone network is momentarily restored, Joon-woo receives a voicemail from his family recording their refuge being overrun. His rage causes him to leave the apartment and attack zombies, but when a horde attacks, he flees and barely manages to sneak back inside.

Joon-woo attempts to hurt himself, but stops when he sees a laser pointer’s light. The signal comes from Kim Yoo-bin, a survivor living in the opposite apartment building. Yoo-bin tries to set up a zip line between their apartments by tying a cable to her table and throwing the other end to Joon-woo, but it lands in the street. Joon-woo uses his drone to set up another line successfully, but an infected firefighter pulls on the first cable, causing Yoo-bin’s table to fly across her apartment, knock her out, and lodge into her balcony railing. The zombie starts climbing the cable. Joon-woo distracts him by sacrificing his drone, giving Yoo-bin enough time to wake up and kill the zombie.