A lawyer with a ten-percent winning rate is caught up in a murder case and becomes the notorious and genius con artist, Big Mouse, overnight. In order to survive and protect his family, he tries to reveal the true colors of the privileged people involved in a huge conspiracy.
Changho, who has no money and is about to lose his wife, receives a call from the mayor of Gucheon.
Changho is charged with drug abuse and locked up in Gucheon Prison.
Changho needs to maintain recognition as Big Mouse to protect Miho.
Gong Jihoon makes a bet with Changho to find out his true identity.
Jihoon approaches Miho to find Seo Jaeyoung's thesis. Does Miho know Changho's true identity?
Miho joins the prison medical volunteer program to meet Changho.
Jaeho warns Changho to stop looking into Seo Jaeyoung's thesis. Miho is suddenly attacked.
Changho is in a mental hospital. Will Changho be able to hide his identity in a state of confusion?
Changho stands as an informant in Seo Jaeyoung's trial, and Jihoon and Jungrak search for Changho.
Changho calls out Big Mouse, and an unexpected character turns up at the agreed time.
Changho shifts the power dynamics in the prison to pressure Big Mouse. Doha plants a new warden.
The warden plans to use the prison riots to take out Changho and Miho.
The hot-plate restaurant is in ruins. The agitated Changho meets someone unexpected there.
Changho makes a tempting offer to Chairman Kang. Doha conspires with Yoongab to get rid of Changho.
Changho prepares for the full-fledged elections against Doha, but Miho's health is in trouble.
The TV debate begins, and the smoking gun that will bring down Choi Doha is at Miho's fingers.
