The Prison — Ending Explained

I could not verify every plot detail of the ending from my research, so this analysis covers only what the sources support. The central twist concerns Yoo-gun's real purpose inside the prison: the sources describe the film as involving an undercover police inspector who infiltrates the jail to get close to the inmate who controls the syndicate. His brawling and apparent fall from grace therefore hides a mission, and his entry into Ik-ho's crime empire is the way in. The prison is a fortress of impunity, and the film builds to a violent confrontation between the two men over control of it. Ik-ho's closing assertion that the place is his reflects how he understood his rule. The most plausible reading is that his claim of ownership is what he cannot give up. The "over-the-top" finale was a common complaint among critics.

Some see the film as pure genre entertainment, a macho action romp in a jail. Others read it as a political allegory in which the prison stands for a nation run by an unaccountable elite and the warden for officials who are figureheads. A third reading frames Yoo-gun and Ik-ho as mirror images, two men of violence separated only by their position relative to the law.