Season 1

5-8 investigates the construction of a new district in post-apocalyptic Korea. Sa-wol and Seul-ah experience an unexpected attack.

Seol-ah begins to investigate the recent tragedy. Sa-wol grapples with guilt. 5-8 discovers a dark scheme taking place in the shadows.

5-8 warns Seol-ah about the chilling facts surrounding her investigation. Sa-wol partakes in an intense tournament in the hopes of becoming a deliveryman.

Sa-wol advances to the final round. Ryu Seok reveals his disturbing plans for the upcoming migration, despite his father's opposition.

In the aftermath of Ryu Seok's ploy, 5-8 plans to take him — and Cheonmyeong — down. Having finally achieved his dream, Sa-wol takes up his first mission.

Confronted with a crisis, Seok executes his endgame. 5-8 and Seol-ah team up to stop Cheonmyeong once and for all.