Park 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.

Who made Changho, Big Mouse, and why? However, he needs to be recognized as such to protect Go Miho.

Is Changho really Big Mouse? Gong Jihoon makes a bet with Changho to find out his true identity.

Jihoon approaches Miho to find Seo Jaeyong's thesis. Does Miho know Changho's true identity?

Has Changho been lying to Miho? Miho joins the prison medical volunteer program to meet Changho.

Han Jaeho warns Changho to stop looking into Jaeyong'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 Jaeyong's trial, and Jihoon and Choi Jongrak search for Changho.

Changho calls out Big Mouse, and they respond. An unexpected character turns up at the agreed time.

Changho shifts the power dynamics in the prison to pressure Big Mouse. Choi 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 prepares for the full-fledged elections against Doha, but Miho's health is in trouble.

The TV debate begins, and Miho almost has the smoking gun that will bring down Doha.