When a new type of infectious disease spreads in a high-rise apartment building, the tenants are separated from the rest of the world. The befuddled, isolated and afraid residents' only hope of survival is in their own hands.
EPISODE 1
Episode 1
Sae-bom, a police officer, starts digging into a case to get points for qualifying for a public rental apartment. While investigating the murder case, Yi-hyun realises something unusual.
EPISODE 2
Episode 2
Sae-bom moves in with Yi-hyun; Sae-bom's neighbours are suspicious of her; Tae-Seok and Yi-hyun team up to investigate the mysterious disease.
EPISODE 3
Episode 3
Sae-bom is suspicious of Tae-seok; news about the mysterious disease is revealed to the public; Sae-bom gets irritated by the banging noise from upstairs and heads there to complain.
EPISODE 4
Episode 4
The sudden lockdown puts Park Seo-yoon in Sae-bom's care; Yi-hyun investigates the fitness instructor's connection to Next.
EPISODE 5
Episode 5
The whole complex gets infected, except for Building 101; Sae-bom and Yi-hyun struggle with the constant conflict between the renters and owners; a lack of supplies prompts the residents to step outside.
EPISODE 6
Episode 6
Joo-hyung visits the gym with a plan to get back at the couple in unit 501; a person is let into the building while another heads out.
Han Hyo-joo
Park Hyung-sik
Jo Woo-jin
Lee Joon-hyuk
Park Joo-hee
Baek Hyeon-jin
Kim Young-kyu
An Gil-ho
Hong Won-ju
Han Sang-woon
