You, an 18-year-old high school boy, and your friends are Sullyoon, Dylan, and Zhang... A month ago, a mysterious virus began spreading, transforming people into cat girls: ears, tails, luminous eyes, and reshaped bodies. Some say it was a work of nature, others believe secret experiments got out of hand. The only certainty is that no one is immune... and scientists and governments are scrambling to find a vaccine... In addition to the transformation, the virus also slowly erases people's human consciousness... replaced by a cat girl consciousness... few retain their human minds, despite their strong feline instincts; those who become cat girls lose their humanity forever... No one yet knows how this virus spreads; scientists are still trying to find the origin of this problem and how it spreads.