The Netflix original series “Black Knight,” starring Kim Woo-bin and Song Seung-heon, explores the life of a deliveryman who offers necessities to people in need on a devastated Earth in 2071.

Based on the webtoon “Delivery Knight” by Lee Yoon-kyun, published from 2016 to 2019, director Choi Ui-seok of “Cold Eyes” (2013) and “Master” (2016) tells the story of Earth in 2071, suffering from toxic air pollution. People rely on parcel delivery services for their most basic needs, including oxygen bottles. Deliverypersons -- known as black knights -- bring not only packages to people, but also protect people from thieves at night.

In this post-apocalyptic sci-fi series, Kim stars as a refugee-turned-legendary deliveryman and knight called “5-8.”

“Until recently, we all had to wear masks (due to the pandemic) and I became curious about how people, maybe, will have to depend heavily on delivery of oxygen in the future,” Kim told reporters during a press conference in Yeongdeungpo-gu in Seoul, Wednesday.

“Shooting ‘Master’ with director Cho was such an enjoyable project and I had a deep trust in him, so I decided to this project as well,” Kim added.

Cho said that producing the six-episode dystopian drama series required a lot of energy, as if he were making two films.

“Each episode contains a concrete storyline with an intro, development, turn and conclusion. Action scenes are also worth watching,” Cho told reporters, adding that he particularly requested that Kang You-seok, who stars as refugee Yoon Sa-wol, become an “action monster.”

Protagonist 5-8 is one of 11 black knights who works as a deliveryman during the day and guards groups of refugees at night. Sa-wol wishes to become a black knight as well after approaching 5-8. Together with Sa-wol, 5-8 wants to change the perception of refugees as the most useless group of people in the hierarchical society.

“I try to do this with every project, but for this particular role I tried to remember myself (as a character) as a refugee who has had a sorrowful life when I was young, thinking about what an ideal world would be like for all groups of people,” said Kim.

Song Seung-heon reunites with the director again 21 years after Cho’s feature film debut “Make It Big.” He plays Ryu Seok, the sole successor to Cheon Myeong Group, which dominates the world with its sales of oxygen.

“During shooting, I began to think a lot about the environment. Not many of us realize the importance of oxygen and I suddenly became afraid that this kind of world may come in the near future,” Song said.

To vividly depict the Earth in 2071 without oxygen, a variety of computer graphics techniques were used to portray the desertification of Seoul and fine dust particles and freckles on the characters’ faces.

Esom stars as Seol-ah, an officer in the Defense Intelligence Command, who saves Sa-wol’s life and supports 5-8 in helping Sa-Wol become a black knight.

“Deliverymen are an essential part of everyone’s life and it was very interesting to read in the script about how they become someone very special in the future,” Esom told reporters.

Esom, who worked with Kim on her 2011 debut drama “White Christmas,” said she was glad to see him on the project, joking they have “survived” together as models-turned-actors.

The six episodes of “Black Knight” will be released Friday on Netflix.