A group of humans wage war against the rising evil of unidentified parasitic life-forms that live off of human hosts and strive to grow their power

A story in which ominous things continue and the secrets of the family are revealed as they suddenly inherit the family mountain from their uncle, whom they had forgotten.

A pastor and a detective, driven by their beliefs, pursue a missing person case, with the pastor seeking retribution after a divine revelation identifies the culprit who abducted his son.

A man investigates the truth behind his long-lost mother's death.

Follows a man who gains the ability to transform into a gaseous state and uses his powers for bank robberies.

After a brutal attack, Jeong Su-in learns she may not be the same person as before. Choi Jun-kyung discovers the monsters are forming an organization.

At her unknown uncle's funeral, Yoon Seo-ha meets Kim Young-ho, a man claiming to be her half brother. Meanwhile, detective Choi Sung-jun chases new leads.

Seo-ha suspects Young-ho may have a hand in a recent tragic murder. An age-old conflict between chief detective Park Sang-min and Sung-jun surfaces.

The police refuse to arrest Young-ho, forcing Seo-ha to ask a private investigator to look for evidence. Sung-jun dives into Young-ho's shamanic past.

Young-ho receives an ominous warning about a family burial ground and runs after Seo-ha. Sang-min hastily orders a search of Young-ho's home.

Seo-ha's attempts at intimidating Young-ho go awry. Sung-jun and Sang-min track down a stranger who may be connected to the killings.

Confronted with the shocking truth about the burial ground, Seo-ha finds herself in peril - and she must devise a last-ditch effort to save herself.

Looking for his sister, Seol Kang-woo investigates Saejin Church, where he finds Su-in. But he soon encounters trouble - and the two fight to escape.

After raiding Saejin Church, Jun-kyung begins suspecting Kim Chul-min is hiding something - later tracking him down meeting with Su-in and Kang-woo.

Despite being on the run, Su-in tries to warn Jun-kyung. But as Team Grey's raid plays out, Su-in and Kang-woo realize it's all part of a bigger plan.

After revealing everything he knows to Chul-min, Kang-woo agrees to help save Su-in. But when the plan goes awry, lives are put at risk.

Su-in meets with Seol Kyung-hee, who requests an alliance. But the parasites' ploy for power goes into full effect - and it's up to Heidi to stop them.