The Spread (S01E04)

The apartment complex is sealed off and quarantined after Min Ji's erratic behavior, caused by the Next drug, raises alarms. The residents are forced to remain inside for a week, regardless of their preferences. Sae Bom and Yi Hyun take it upon themselves to isolate the potential threat, Ju Hyung, while also offering refuge to outsiders. As they work together on the investigation, Yi Hyun and Tae Seok uncover that the dealer behind the Next drug operates out of Building 101.