Mr. Shin, a fried chicken shop owner, is known as the neighbourhood problem-solver, quietly mediating disputes between locals. One day, rookie judge Cho Pillip is unexpectedly assigned to work out of Mr. Shin's chicken shop. Neither of them is happy working with each other. Soon, they're forced to work together when Chief Judge Kim Sang-geun asks them to mediate a bizarre case involving a lawsuit over fermented shrimp paste with maggots. Their journey takes them to the small city of Gangchun, where clashing ideologies, quirky locals, and strange legal dilemmas await.

After narrowly escaping a life-threatening situation during a legal mediation, Mr. Shin begins to uncover a massive conspiracy hidden behind a group of salted seafood merchants. Curious about Mr. Shin's true identity, Pillip quietly begins to investigate him. Meanwhile, Mr. Shin takes on a new case. At the same time, a video of a man wearing a bomb vest begins to go viral.

Mr. Shin steps in as a negotiator representing the hostage-taker. Risking his life, Mr. Shin leads tense negotiations in a desperate bid to save both the hostage and the perpetrator. Meanwhile, Pillip and Officer Kim uncover the illegal ties between Yongdan City and the fertiliser factory, and urgently relay the information to Shin. However, the negotiation ultimately falls through, and a deafening explosion erupts, engulfing the site in flames.