Choi Do-Ha is the primary antagonist of the 2022 South Korean TV series Big Mouth.
He is the mayor of the city of Gucheon and the archnemesis of lawyer Park Chang-ho and the criminal mastermind Noh Park aka the Big Mouse.
Plot[]
Choi Do Ha is the grandson of a scientist who works for Kang Seong-geun's NK chemical company. After his grandfather discovered that the chemical was causing harm to the environment and health of the locals, he urged Kang to stop the production but Kang disregarded this and continued with the production for profit, causing him to resign in disgust. Fearing that Do-Ha's grandfather might unveil his company's wrongdoings, he orchestrated a car bomb resulting in the death of Do-ha grandfather and younger brother. Do-Ha swore revenge against Kang by working under him to slowly gain his trust to one day killing him and taking over his assets. Eventually he was appointed as mayor of Gucheon City.
Park Chang-ho, a lowly lawyer with low rates of success in defending client, is framed to be the criminal mastermind that rules the entire South Korean Underworld nicknamed Big Mouse after taking on the case that involved the murder of a university professor who possesses a critical research that links to the harmful effect of the chemical manufactured by Kang's chemical company. In prison, he is instructed by the real Big Mouse to act on his behalf for reason unknowns. Taking advantages of the Big Mouse persona and vast connections in the law enforcement, he managed to make prison life for himself and the inmates better while trying to figure out who is the Big Mouse.
Eventually, Chang-Ho learns that the real Big Mouse is none other than his cellmate, Noh Park. Noh Park reveals his reason to frame Chang-Ho is because the murder case he took related to his own daughter, an investigation journalist, was brutally murdered by Choi Do-Ha while she was investigating Kang's company. Eventually, Noh Pak Park used his influence to get him and Chang-Ho out of prison. Do-Ha eventually assassinates Noh Pak by bombing his restaurant while Noh Pak is inside. Before his death, Noh Pak appointed Do-Ha as the new Big Mouse due to Chang-Ho had proven himself to be a determined and resilient man while in prison.
As the New Big Mouse, Chang-Ho creates a law firm to defend the weak and the poor while seeking to bring justice against Do-Ha and his goons. Do-Ha eventually arranges for the death of Chairman Kang and subsequently takes over his assets and company.
Chang-Ho eventually manages to gather enough evidence to prosecute Do-Ha by convincing Do-ha's wife to testify against her husband but Do-ha locks his wife in a mental asylum, enabling him to escape justice as his wife unable to testify against him. Furthermore, Chang-Ho's wife passes away from cancer due to the chemical dumped by Kang's company which now under the control of Do-Ha and continues this activity. To matter worse, Do-ha wins the election to be Mayor again.
Having had enough with the failing justice system, Chang-Ho confronts Do-Ha in his swimming pool. Do-Ha mocks him that Chang-Ho cannot do anything against him even if he is the biggest criminal mastermind in South Korea. Chang-Ho then reveals that he had poison Do-Ha swimming pool with the same chemical, his company dumps in the river that poisoning people including his deceased wife. Do-Ha is shocked at the fact and cough off blood from the effect of the poison, which he then falls backward to his demise in his own swimming pool, killing by the same chemical that his own grandfather fought against.
To ensure his legacy goes down in flame, Chang-Ho rescues Do-Ha's wife who unveils all her husband crime to the public, making his legacy tarnished beyond the grave.