After a near-death experience, Mu-jin strikes a strange deal with a mysterious figure named Bo-sal. But in return, he begins to see terrifying ghosts with grudges. Haunted by the spirit of Min-uk, Mu-jin gets pushed to investigate the unsafe factory where Min-uk died. Gyeon-woo goes undercover as a new hire and meets Nimal, a migrant worker afraid to speak out, but as the truth surfaces, the team is exposed and forced into a desperate retreat.

Mu-jin and his team look for evidence to reclassify Nurse Cho Eun-young's suicide as an industrial accident, aiming to hold the hospital accountable for covering up suspected workplace bullying and medical malpractice. However, with Mu-jin blacklisted from the hospital, it falls to Gyeon-woo to infiltrate the facility and locate the one piece of evidence Mu-jin remembers seeing while possessed.