동주와 조세5국 팀원들, 조세5국으로 탈세 제보가 들어온 오즈식품, 그리고 오즈식품과 결탁한 국세청 내부 관계자를 밝혀내려 한다.
As someone died while trying to tip Bureau Five off, Dong-joo and his team are determined to find out who is the betrayer. Dong-joo pulls a trick and blows the whistle on someone inside the NTS in front of the Commissioner at a meeting. A tax evasion case suddenly turns into an internal corruption investigation.