Citizens from upscale Gangnam in Seoul start experiencing unusual and terrifying symptoms, devolving into inhuman creatures, leaving only a few survivors with the possibility to make it out alive.

A story of a young prosecutor who has suffered a new opportunity to realize justice again. Adapted from a web novel of the same name.

Eun Ha-Won is a college student. She is a bright girl who wants to be a veterinarian, but at home she is lonely. She is isolated from her family members. Eun Ha-Won lives with father, step-mother and step-sister after her mother died in a car accident. One day, she helps a mysterious old man. The old man suggests to her to live in a mansion and pursue her dream of becoming a veterinarian. Since than, she moves into the mansion and lives with three cousins Kang Ji-Woon, Kang Hyun-Min, Kang Seo-Woo and their bodyguard Lee Yoon-Sung.

Kim Tae Hyun is a promising young surgeon, but his finances take a dive when his sister's health condition requires costly dialysis treatments. When Tae Hyun subsequently falls into a vicious cycle of debt, he assumes the alias of "Yong Pal" and begins making house calls for criminals who are willing to pay top dollar. Complicating things further, Tae Hyun gets involved with Han Yeo Jin, a comatose patient at the hospital.