: He forms a tense partnership with Oh Soo-yeon , a successful businesswoman with a dark past seeking her own retribution, and Jang Sun-oh , a gambling genius who controls the prison's underground games. Cast & Characters
(Lee Yoo-young): An ambitious businesswoman who assists Yo-han for her own vengeance. : He forms a tense partnership with Oh
: At the suggestion of senior prosecutors, Yo-han goes undercover into Seongju Prison to gather evidence against a corrupt gambling ring and a high-ranking prosecutor. is a 2022 South Korean action-suspense thriller following
is a 2022 South Korean action-suspense thriller following a judicial trainee who enters prison undercover for an investigation and finds himself embroiled in a high-stakes survival game. Core Story & Plot To survive and seek revenge for his grandmother's
(Kim Sang-ho): A senior prosecutor who initially sends Yo-han undercover but whose motives become murky. Series Information
: He discovers that the prison is actually an extensive underground gambling den. To survive and seek revenge for his grandmother's death, Yo-han must use his "poker face" and intellect to rise through the ranks of the prison's gambling world.
: His mission goes sideways when his superior is murdered and his colleagues disown him, leaving him "trapped" as a real prisoner.