After a sabbatical, Detective Wu Ming-han and his new captain Lin Tzu-ching take on a puzzling murder that leads them to a notorious killer behind bars.

A third murder occurs, alluding to yet another cryptic Chinese idiom. Left with no other choice, the cops must enlist Shui-yuan's help with their cases.

A strange phone call points the police to a suspect and his private home. Meanwhile, Wu Ming-han decides to chase down a different lead by himself.

As Shui-yuan's past unfolds, the police find more clues about the current cases. Following a famous tutor takes Ming-han down an unexpected path.

Shui-yuan's meeting with Huang Hsian culminates in a colossal misunderstanding. To lure out the killer, Chang Yung-kang makes a risky announcement.

As an unprecedented crisis grips GG Precinct, Ming-han's instinct guides him to someone who has slipped under the radar the entire time.