The Hero must escort Jin to the old bunker, and blow up the entrance in order to gain access to it. Then, the two must get to the tunnel through the old bunkers. Finally, the two must reach the Jungle and search for Mowen.
It has been reported that players who are playing this on version 1.0.0-1.1.0 have experienced a bug which forces them to start a brand new game because of certain problems with this quest. Upon accepting the quest, the players have decided to walk away and do other quests and come back (which is rather common in the game). However, upon leaving the vehicle that Jin gets in, a timer counts down until the player fails the quest, then the spawns the players far away from the vehicle and gives them no time to get back to the said vehicle. This bug makes it impossible to continue the game or do other available missions.
Another bug is when the player kills an Infected and they're electrocuted. If Jin touches the electrocuted zombie, there's a chance she'll fall down but she'll get back up. Though it won't harm Jin directly, there may be a chance she might not get back up.
If the player jumps the fences of the bunker and gets behind it and then jumps off the hill, they will respawn actually inside of the bunker. The only way to proceed with the quest is to load last checkpoint, or commit suicide because if any action are done inside the bunker that could cause the game to save the player's progress, this savegame is rendered useless and the player is forced to start a brand new game.