In need of a cellphone, two students take a risky journey to the teachers’ office. Byeong-chan passes on critical information to Detective Song Jae-ik.

When one of the group is scratched while fighting a zombie, Lee Na-yeon demands they kick him out. Outside, the virus swallows up the city.

The infected multiply in droves. Scrambling for their lives, Nam On-jo and Lee Cheong-san find safety with others inside a classroom — but not for long.

The team scouts the apparent hub for the aliens’ food supply, only to come face-to-face with a full-fledged invasion. Meanwhile, Auggie’s attempt to sell out his son to the police…

An unexpected ally emerges.

Ready to pursue his next dream, Ung sets his sights on studying overseas. When he asks Yeon-su to join him, she has a tough decision to make.

A noticeably down Ji-ung pours himself into his work instead of going home. Ung waits for Yeon-su to come and see the final night of his art exhibit.

Young Min openly shares the secret of what happened 12 years ago, and at the same time, Seung Tak shares his side of the story regarding Young Min’s cardiac tamponade…

Thony is given a dire ultimatum by Garrett that could compromise her son’s access to medical treatment. Arman is tasked with collecting large “donations” for Hayak’s daughter’s wedding, calling into…

Young gets stabbed by Merchant Sim right before he meets Ro Seo, and he even tells him that he will go after Ro Seo as well. Inspector Kim and Officer…

Merchant Sim fails to murder Young and Ro Seo because Si Heum shows up to protect Pyo. After that incident, Pyo realizes that Si Heum and Chief State Councilor were…

The final face-off against Myeong-hwi tests Mun and the other Counters’ limits. In Yung, long-awaited reunions take place.

The team welcomes back a Counter who’s been overseas. After confirming his suspicions about his father, Shin Hyeok-u goes to Mun.

Myeong-hwi’s son notices something about his father isn’t quite right. When Baek Hyang-hui kidnaps a young girl, the Counters rush after her.

As Cheong-sin becomes nearly unstoppable, the Counters learn there may be a way to defeat him for good. Mo-tak gets justice for Jeong-yeong.

A heartbroken Mo-tak and the team plot revenge against Shin Myeong-hwi and his collaborators. While carrying out their scheme, a human corpse turns up.

The Counters struggle in a mismatched fight against an increasingly dangerous Cheong-sin and the other demons. Mo-tak’s memories resurface.

Wi-gen calls for an action that could take everything away from Mun. When stunning news about Cheong-sin is reported, the Counters can’t believe it.

Cheong-sin leaves Mun in a bad state, but Chu Mae-ok is determined to save his life. The Counters set out to make the mayor’s corruption public.

Things get personal for Ha-na as she takes down a familiar demon. The team tries to locate a reservoir tied to a case Mun’s father had worked.

During a trip into his most traumatic memory, Mun has his first encounter with Ji Cheong-sin. Later, he leads the Counters to a car junkyard.

While the Counters attempt to keep the truth behind his painful past from Mun, he discovers a mysterious memory card among his parents’ belongings.

Do Ha-na saves Mun from the attacks of a powerful demon with a malicious tongue. Kim Jeong-yeong helps Mo-tak look into his last detective case.