"The Insider" is a Korean action suspense TV series released in 2022
The protagonist Jin Yaohan is a Sima trainee and lives with his grandmother. Since he had no background, he was assigned an undercover mission by his superior when he first came to work in the Judicial Yuan. Jin Yaohan finally accepted the task of undercover. When Jin Yaohan came to the prison, some prisoners came to harass him, but Jin Yaohan ignored him, and did not resist the beatings of other prisoners. In order to get in touch with Li Guangtai and hope to get evidence from him, Jin Yaohan began to learn gambling skills in prison. Jin Yaohan found out that his grandmother had died in prison, which shocked him very much. Jin Yaohan came to the camp of the leader Zhang Shanwu in the prison. Through the investigation, Jin Yaohan suspects that Zhang Shanwu killed his grandmother. Through layers of obstacles, Jin Yaohan successfully obtained evidence from Li Guangtai and pointed to Yin Bingxu. In Yin Bingxu's final trial, he admitted his crime.