Gyeongseong, 1945 — and Seoul, 2024. A pair adrift in time fight for survival against monsters born of human greed.

A high school becomes ground zero for a zombie virus outbreak. Trapped students must fight their way out — or turn into one of the rabid infected.

Choi Su Jung, a 16-year-old high school student, is brutally murdered by a serial killer. Her friend Young Jin gets to take a phone call from the killer and says that she’ll find and kill him. Over two decades later, Young Jin has become a police officer and still desperately tries to find the serial killer. She has a young, middle-school-student neighbor Eun Ho. He gets shocked by what’s inside Young Jin’s room when he comes over to her place.