When the ostensibly unblemished prosecutor Kim Seokgyu is nominated for Minister of Justice, the opposition party raises questions about the 1994 "Migeum Arson-Murder Case." They allege that he conducted a coercive investigation against the illiterate suspect Hong Sunhwa and sought the death penalty; however, the crisis passes when a letter left by her comes to light. Yet, after belatedly reading her plea for her innocence to be conveyed to her son Eunsu, Seokgyu begins to reinvestigate the closed case. A prosecutor who once sought justice only within documents and courtroom walls confronts the truths he had overlooked through the voices of those involved.