Ten years ago, death rates of human beings rose to 5.2% a day which has caused concern. It became a sensational topic as the dead bodies would be found mutilated or appear being eaten. At first, it was thought to be done by evil criminals but then the government found the existence of human beings who appears to be 'human' but rather has hidden animalistic characteristics. They are named "MOUG".
To make the citizens calm down with the growing death threat, many incidents are kept secret and social media is controlled by the government. This is why, even after ten years, the existence of MOUGS are not known to many people especially the younger generation.
As technology advanced, weapons against these MOUG developed. The government established military academies that specialized with exterminating them.
Ha-il, an ordinary senior high school student, found her parents mutilated after going home from school. Due to trauma, she was sent to mental hospital for five years. When she was released, she suddenly felt like she is being monitored and protected.
Season 4 of The Virus Within
Trinity is familiar with zombies, being one herself, but when strange zombies start appearing, she realizes that the world she knew might be changing yet again.
When a dangerous set of scientific notes are discovered, Trinity and her friends don't realize anything is wrong until a frantic radio call comes in. Unaware of the notes, they race to the south and struggle to determine where the strange zombies came from. The zombies are unlike any ranks previously seen, and they aren't as predictable. Some have new tricks hidden up sleeves, forcing any Stronghold they encounter to quickly adapt to the new challenge or risk being overrun. Secrets never remain hidden, and zombie apocalypses never make life easy.