Introduction of main characters:
M--The eldest brother, DD's elder brother, was lost with DD when he was young.
J--□□ thug, S's junior fellow student, another undercover agent of the police.
A classmate at the R--S Police Academy, he later held an important position in the police station.
S--Police, undercover, codenamed "Wind"
W--Police psychologist.
D--S's childhood sweetheart and student.
Jiang Hodong - the boss behind the scenes, admired M and J and S who later joined, and committed suicide when the gang was disbanded.
Shin Jung-hwan—the bad guy who fought with M. He was jealous of M and indirectly killed J. He was later eliminated by RS (Qian Jong was his brother)
Li Zhen - a perverted rich man with pedophilia.