Some kind of mercenaries appeared at the processing station and I'm dying to know what they're cooking... Sneak into their camp and dig up whatever information you can about their plans. PDAs, paper documents, bring me whatever you find. You got me? Go. It's nothing but kid stuff if you keep it quiet.Owl
Mercenary Camp is a side mission available in S.T.A.L.K.E.R.: Call of Pripyat.
This mission is offered by Owl and is available from the start. Owl asks the player to sneak past the Mercenaries inside the Waste Processing Station in Zaton to see what the mercenaries are doing here.
If the player is spotted in the surrounding area, they will be warned by the mercenaries, and the game will auto-save if such option was activated. If the player stays for too long around or inside, they will open fire at the player.
The player must retrieve the Mercenary notebook which is located in the second floor of the complex.
The simplest way to get the notebook is by eliminating the mercenaries in the station. While the mercenaries aren't especially hard since most of them are only armed with Viper 5s and AKM-74/2s with Hook and Ridge the only ones armed with customized TRs-301s, the difficulty of the fight comes from the complex itself, as the floors that lead to the notebook are see-through, making it easy for mercenaries below or above the player to shoot them as they proceed through the building. Moreover, it is dark inside, prompting one to use night vision. It is not obligatory to eliminate all the mercenaries, although killing Hook and Ridge will allow the player to loot their PDAs and sell them to Owl for an extra reward. This also allows the player to take the loot in the area - there are various kinds of ammunition and supplies there.
This is best done in the evening. This approach requires stealth and silence - regular quicksaves can help if the player gets spotted. The entrance to the short sewer running below the facility is located on the north-eastern side of the area - simply drop into the hole while taking care not to be seen by the patrolling mercenaries. The player will arrive at the bottom floor. Now the player needs to sneak to the top floor without being seen - night vision can help locate the patrolling mercs. Once at the top floor, grab the notebook then go away - the player may get spotted and quickly escape but this won't matter.
Wait until the trip to Pripyat
If the player completes the Pripyat 1 mission before going through the mission, the mercenaries will disappear (as evidenced by the mercs' PDAs and Yar, they waited for someone to be able to reach Pripyat to move out). The marker will point the player towards the aforementioned tunnel where lies a dead mercenary holding the notebook in his inventory.
Likewise, one will not be able to get Hook and Ridge's PDAs.
Once the notebook is found, bring it to Owl to complete the mission.