Season 1
Park Changho is known since his school days as "Big Mouth" because he talks big and promises big things but cannot follow it up. He is also an infamous lawyer with a very low rate of success who was hired by a mayor because of his incompetence. Unfortunately, he was framed as the notorious and mysterious swindler "Big Mouse" and sent to prison. Go Miho is Changho's loving wife who works as a nurse. She has strong personality and will do anything to prove the innocence of her husband and help solve the case the mayor has given to her husband. Will Miho be successful in proving her husband's innocence? Or will her investigations lead to opening a can of worms?
Episodes
Episode 1
Changho, who has no money and is about to lose his wife, receives a call from the mayor of Gucheon.
Episode 2
Changho is charged with drug abuse and locked up in Gucheon Prison.
Episode 3
Changho needs to maintain recognition as Big Mouse to protect Miho.
Episode 4
Gong Jihoon makes a bet with Changho to find out his true identity.
Episode 5
Jihoon approaches Miho to find Seo Jaeyoung's thesis. Does Miho know Changho's true identity?
Episode 6
Miho joins the prison medical volunteer program to meet Changho.
Episode 7
Jaeho warns Changho to stop looking into Seo Jaeyoung's thesis. Miho is suddenly attacked.
Episode 8
Changho is in a mental hospital. Will Changho be able to hide his identity in a state of confusion?
Episode 9
Changho stands as an informant in Seo Jaeyoung's trial, and Jihoon and Jungrak search for Changho.
Episode 10
Changho calls out Big Mouse, and an unexpected character turns up at the agreed time.
Episode 11
Changho shifts the power dynamics in the prison to pressure Big Mouse. Doha plants a new warden.
Episode 12
The warden plans to use the prison riots to take out Changho and Miho.
Episode 13
The hot-plate restaurant is in ruins. The agitated Changho meets someone unexpected there.
Episode 14
Changho makes a tempting offer to Chairman Kang. Doha conspires with Yoongab to get rid of Changho.
Episode 15
Changho prepares for the full-fledged elections against Doha, but Miho's health is in trouble.
Episode 16
The TV debate begins, and the smoking gun that will bring down Choi Doha is at Miho's fingers.