Three officers are suddenly transferred to Seoul. They are considered the best of the best in their region. Taeyeon from the north, Yuri from the south and Tiffany is remained a mystery. Taeyeon has a fun personality and gets along with anyone while Yuri is quite the opposite. Always going off on her own and not taking orders. Tiffany is the calm one and she keeps Taeyeon and Yuri in order. Together the three of them are sent off on team missions, investigating murders and other crimes.