In Seoul gangs run rampant in the underground society, and the city's most notorious gang leader, Poseidon, is dead. Knowing how and why Kwon Yejin flees from 3.6.5, Poseidon's gang, to find help in the leader of the Circle --an organization that acted as a contract hub for the city's gangs-- with only a gun and a piece of paper to prove her worth to its leader, Xiumin.    Yejin grew up around 3.6.5 with her best friend, Tao, who worked at the 7Seas casino, so they knew how that wo