In an era where the VP virus (Vampire Virus) has spread, humans infected by the virus become zombies with only the desire to suck blood remaining. Working as a level 6 agent at the organization 'Crimson Lake' that deals with the infected, Baek Shin-hee hides her true identity. Although her position as a level 6 agent conceals her identity, Baek Shin-hee is actually a special secret agent with incredible superpowers. One day, a new agent named Joo Yeong-ah appears before Baek Shin-hee, who has always operated independently while hiding her identity, and she encounters the unfamiliar existence of a partner for the first time. The moment the top elite Joo Yeong-ah, who graduated at the top of her training school, first meets Baek Shin-hee, she says, "I don't respect you. I don't like you, senior." Baek Shin-hee feels a strange interest in Joo Yeong-ah's words of dislike.