The series centers on a group of high school students in the fictional South Korean city of Hyosan, and their struggle to survive amidst a zombie outbreak.

In the South Korean city of Hyosan, a hopeless science teacher enacts a horrific experiment, causing a local high school to be overrun with zombies.

As the outbreak spreads to the city, and the beleaguered authorities struggle to contain it, a group of trapped students must band together and use their wits in order to survive and reach safety.

On April 12, 2020, Netflix announced through a press release that JTBC Studios and Film Monster would produce a series called All of Us Are Dead based on the popular webtoon Now at Our School.

[44] In selecting the cast, director Lee Jae-kyoo said, "I thought that bringing on actors who were great at acting but still unknown to the public would add to the immersion of the series".