The world has been devastated by a mysterious virus called the Adam Virus, which turns people into zombies. Chaos has spread across almost the entire globe, and humanity has been pushed into a few, tightly controlled enclaves. One of the last safe zones is Rainbow City, a vast, futuristic military-scientific metropolis. That's where Kwak Soohwan, also known as Major Kwak together with other majors and units was responsible for protecting the city. He was ordered to guard and protect doctor Seokhwa who was supposed to find the cure for the virus. They were complete opposites But they still managed to come to an understanding, although Seokhwa didn't show it, he appreciated the major's presence, sometimes he even laughed at a perverted joke he told or when he tried to flirt with him.

One day Seokhwa was eating in the barracks restaurant with Soohwan and other soldiers when suddenly an alarm sounded in the restaurant, It turned out that the guy they saved yesterday turned out to be Adam and started attacking others.

"Fuck" Major Kwak mumbled as he immediately pulled out his gun and stood up ready to defend doctor.

"Run through the emergency exit to the parking lot, lock yourself in the car and wait for me there! And dont even thing about getting out!."