SINGAPORE – In the year 2071, air pollution has killed off most of the human population and oxygen masks are now required in order to survive.

South Korea has become a desert and a brutal dystopia with a strict class system. Those deemed important enough are stamped with a QR code that allows them to receive necessities, while those without, termed refugees, are left to fend for themselves.

Deliverymen, who have to deliver oxygen to people while fending off bandits, have become crucial to the world.

That is the story of K-drama Black Knight, which premiered on Netflix on Friday and stars South Korean actor Kim Woo-bin (Our Blues, 2022) as the legendary deliveryman known only as 5-8.

At night, however, he transforms into a “black knight” – a protector of the refugees – who is working to take down Cheonmyeong Group, the corporation that controls the oxygen supply of the world.

While the show may be fictional, the issue of pollution, mask-wearing and climate change is not. And the cast members say Black Knight has heightened their awareness of such issues.

“Until recently, we were all wearing masks, so this felt like a probable future to me,” Kim, 33, says at a press event in Seoul on Wednesday, with regional media attending virtually.

Co-star Song Seung-heon, 46, adds: “During filming, I thought about how we take fresh air for granted when it’s so scarce and such a critical resource in this series.

“We know that there is climate change, we know that ice is melting, but we don’t treat it as such a big deal and we stay very complacent. But a lot of experts tell us this could be very destructive. Black Knight is my way of raising awareness of environmental changes and I hope it does the same for other people too.”

Kim, Song, actor Kang You-seok and actress Esom share four things about Black Knight.

1. Dry, decrepit world

One of the highlights of Black Knight, says 33-year-old Esom (Taxi Driver, 2021), who plays military officer Seol-ah, is the immersive world it creates.

She says: “We really tried to get across the dry, decrepit vibe of this dystopian world. The palette is kept very dark, all of us have freckles on our faces from the weather and have QR codes on our arms.”

And while the year is 2071 and the world is nearly unrecognisable in the series, Song says there will still be some references to the current world.

“You’ll see the (Seoul landmark) Namsan Tower and other buildings in Seoul that are so familiar, but in a completely different setting. I think a lot of people will find that very refreshing.”

2. Wefie-loving villain

Song, best known for romantic hero roles in early Hallyu (Korean wave) dramas such as Autumn In My Heart (2000) and Summer Scent (2003), takes on a rare villain role here as the heir of Cheonmyeong Group who wants to rule the world with oxygen.

While he may be the bad guy on screen, the cast and series writer-director Cho Ui-seok – who worked together with Song on the comedy film Make It Big (2002) more than 20 years ago – says Song is a big joker who loves to take photographs with the cast on set.

But Song just wants to be prepared when it comes to his wefies.

“Sometimes, when I’m done with a project, I want to post the photos on Instagram, so I don’t feel good if I don’t have the pictures ready,” he says.

3. Model leads reconnect

Black Knight marks a reunion for Kim and Esom, who worked together on the mystery thriller White Christmas (2011) as rookie models-turned-actors more than a decade ago. And they had fun reminiscing about the past.

Kim says: “We talked about the old days and were like, ‘Wow, we survived in this industry, huh?’ We used to get scolded by directors for our performances, and now we’ve both grown and become these solid actors, I guess.”

4. Action titan

Also joining the cast is Kang (Payback: Money And Power, 2023), who went through fiercely contested rounds of audition to nab the role of Sa-wol, a refugee boy taken in by Seol-ah who aspires to be a deliveryman like 5-8.

Many of his scenes are action-driven as Sa-wol trains to be a fighter as strong as 5-8. In fact, he was told by Cho that he needed to transform himself into an “action titan”.

“I felt a lot of pressure and I knew it would be a bumpy road ahead,” the 28-year-old says. “So every day for three months, I went to work with the stunt team and went for lessons in action scenes. It really wasn’t easy.”

Black Knight premieres on Friday on Netflix.