A Self-Righteous Man (1988)

As the tragic war of fratricide is drawing to a close, a special agent nicknamed Dokbul, Kang Cheol-gu, is given an intelligence mission to identify and confirm the enemy's unusual movements. While on a mission, Cheol-gu infiltrates the enemy's camp alone and accidentally witnesses a bloody scene of massacre of civilians. He saves the only survivor, Hwang No-in, and is hinted that the enemy's plot is very dangerous. Cheol-gu approaches Mi-young, a People's Army nurse, to extract information, but is exposed to the enemy and escapes a crisis after a fierce battle. In the end, thanks to Cheol-gu's persistence, Mi-young realizes the illusion of the liberation struggle they are calling for, and transforms into Cheol-gu's collaborator to stop their horrific plot, germ warfare, and carries out the mission. However, the result of this tragic war is only futility. A war of illusions where more is lost than gained, and in the end, even the nickname Dokbul sheds hot tears.

Unfortunately the movie A Self-Righteous Man is not yet available on HBO Max.