In the second season of D.P., Ji-seop is asked to reopen the case of Na Jung-seok’s death. Ji-seop soon realizes that the truth is very different from what he had imagined it to be.
Staff Sergeant Na Jung-seok was Ji-seop’s close friend. He died while saving a subordinate from an old Guard Post (GP) landmine. It was an open-and-shut case, but his family as well as Ji-seop, who placed him on that post, raised suspicions.
Now, the Human Rights Division wants to investigate the case again, and General Gu chooses to send Ji-seop to GP to do the same. What Ji-seop does not know is that General Gu is already aware of how Jung-seok died, and that is precisely why he is sending Ji-seop to investigate.
What made Ji-seop suspicious?
Ji-seop believes that the military had covered up the truth about Jung-seok’s death because the EOD log had clearly stated that the old landmine could not have caused the kind of damage that was seen on Jung-seok’s body.
Furthermore, the night before his death, Jung-seok called Ji-seop very late. The phone call was odd because Jung-seok was reminiscing about their past. The way he talked about life made Ji-seop think that his seniors at GP were giving him a hard time.
The next day, Jung-seok died, and Ji-seop doubted that he was killed by a landmine. Almost a week after his death, he was designated as a person of distinguished service.
However, his death was not investigated the way it should have nor was a proper autopsy performed. Now that he has been given a chance to uncover the truth, he is determined to get to the bottom of it.
Ji-seop’s prime suspect
At the time of Jung-seok’s death, the only person who did not give an alibi was Shin A-hwi, the subordinate who was saved by Jung-seok. Additionally, Beom-gu tells Jun-ho that before his death, Shin A-hwi kept confronting Jung-seok.
A-hwi does not leave a good first impression on Ji-seop and Jun-ho. When they interrogate him, he does not bother telling them anything. His insincere responses and attitude annoy Ji-seop, who starts believing that A-hwi was bullying Jung-seok, even though Jung-seok was his senior.

As A-hwi and Jung-seok were the only two soldiers who entered the restricted area that night, Ji-seop thinks that the two of them must have argued before the landmine killed Jung-seok. He also thinks that this was covered up because it would have created trouble for everyone.
How did Jung-seok die?
To find out the truth, a frustrated Jung-seok locks himself in a room with A-hwi and beats him up. A-hwi still refuses to talk, as he thinks that Ji-seop will not believe him anyway. Ji-seop even ends up setting the room on fire.
When Beom-gu gets there, he tells Ji-seop that it was Jung-seok who breached the codes of conduct, not A-hwi. He got drunk and called many people, including Ji-seop. What Ji-seop considered to be a cry for help was nothing more than a drunk call.
A-hwi and Jung-seok both went to the restricted area on the night of Jung-seok’s death, and Jung-seok harassed A-hwi, who did nothing but follow his orders. A-hwi warned Jung-seok about the mines when he kept pushing him, but Jung-seok did not listen.

When A-hwi could not take it anymore, he defended himself by pushing Jung-seok, who got up immediately and tried to attack A-hwi but stepped on an old landmine instead. The ensuing blast killed him and injured A-hwi.
GP soldiers covered up the truth because A-hwi would have faced a court-martial, and it would have been hard for him even if he claimed to be innocent. The incident changed A-hwi for the worse.
Despite knowing the whole truth, Ji-seop cannot expose it. If he does, Jung-seok, his friend, will no longer be seen as a hero who saved his subordinate, and his parents will stop receiving a pension. Ji-seop ends his investigation and decides to give the same report as the initial one, which is exactly what General Gu wanted.
