[y/n] is a undercover spy, who works at a sketchy bar in Seoul, South Korea. Her mission is to find out who has been taking information from inside the group, and she is suspicious of her partner, Jeon Jungkook. But, on the other end, Jungkook is suspicious of his partner, [y/n]. When they are both assigned to the same mission as partners, they both keep their distance. Who is the fake, and is it even one of them?