As soon as you leave the initial area of the Zone and meet the new Iskra group of stalkers in S.T.A.L.K.E.R. 2: Heart of Chornoby, Skif will receive a new task. Pripoy turned out to be just a pawn, but he gave a lead on a scientist named Nestor. Richter believes that it is the stalkers from the Isolator who will help Skif in his search, but, as is usually the case, they need something in return.
The leader of Iskra, Star, wants to free his people, who have been blocked by the military at an old factory. According to Star, one of Nestor's hideouts is also there, where Skif can find a new clue. Star immediately makes it clear that he is not interested in the death of the military, so you can complete the quest in different ways. Additionally, you will be given a silenced pistol.
After talking to Star in the Isolator, you can explore the surroundings a bit. Talk to the stalker Kunitsa, who is standing at the entrance to Star. He will tell you that something has started up in the basement of the isolator, but the passage is closed. The key is somewhere on the first floor. Do not go down the stairs, but go deeper into the floor you are on. In the cells, you can find medkits, anti-radiation drugs, and ammo.
When you reach the end of the floor, go down to the first floor. On the right, there will be a room with a table. In it, you can find bandages, vodka, and the basement key. The lower floor is similar to all the previous ones, meaning it has two entrances. A small secret is that it is better and safer to enter the basement not from where you found the key, but from the side where the stalkers are sitting. You will see many fiery anomalies and can find an artifact with a detector, but the path to it will be significantly shorter. The artifact improves fire protection but moderately increases radiation. There is nothing more to do in the isolator, so head to the factory.
The factory is very close to the isolator, but if someone notices you, they will immediately open fire. The entire area is surrounded by a fence with several entrances. Most likely, you will first reach the entrance where one guard is standing and looking through binoculars. Do not go there, as the entire base will immediately raise the alarm.
Move so that the fence is on your left. You will bypass the building and see a hole. There is a pipe that will lead to the second floor of the building, and a hole under it, through which it is convenient to penetrate the first floor.
Here you should remember Star's words about stealth, but there are a few facts that are useful to immediately understand about stealth in this game. You can indeed enter some locations from different places, but in the dark, nothing is visible, and the flashlight attracts attention. If one person notices you, everyone notices you. Over time, the alarm may subside, but this happens very rarely, as all enemies are magnetically attracted to your position. To prevent this from happening, you need to go really far away, which is impossible within a confined space. Moreover, you cannot quietly knock out a person from behind, and body shots do not kill instantly, meaning you always need to aim for the head, which is harder to do from behind — for example, the soldier might be sitting.
In the end, it doesn't matter much how exactly you get to the base; most likely, you won't be able to sneak in completely unnoticed.
Your side task is to find Star's people. You will automatically complete it while doing the main quest, but a few clarifications are required. On the second floor of the factory, there is a door with a lock. If you open it (by hitting the lock with a knife), you will find a prisoner. Talk to him. The stalker will tell you that the rest of the people are being held in a basement laboratory two floors below. Additionally, he will ask you to get secret documents.
To find the entrance to the basement, you will have to look around. There are only two places in the entire factory where the staircase goes below the first floor. In one case, the door will remain locked; in the other, you will find a code lock.
To find the right descent, exit the room with the prisoner back to the floor and stand so that the room is on your left. On the right, you will see a breach in the wall and an exit to the main factory area outside. Head there and notice the descent down a collapsed concrete slab to the first floor. You can get here in many other ways, but this is the fastest.
As soon as you are on the first floor, turn around — the staircase will be directly ahead, slightly to the left. You do not need to enter the main factory building. You already know the code for the door, but just in case — 2605.
On the lower floor, go past the old elevator down the ruined staircase. You will find the first stalker corpse. Further to the right is a toilet with a medkit. Go straight — a bloodsucker will appear. Kill it and inspect the room. At the far end is a table with a recorder on it. Listen to the recording and exit the room where the toilet and main corridor are. Turn right and you will see an electric anomaly flying in a circle. You need to move in such a way as to avoid taking unnecessary damage. Stick to the left side until an unknown person contacts you. Ahead of you will be a room with a stalker corpse to the right and a fire anomaly even further to the right. Note that behind it on the ground lies a red folder that looks like a medkit. These are the secret documents. Be sure to pick them up.
There is nothing more to do here, so return to the very beginning to the ruined staircase. When the available steps end, you will see a beam that you can climb. There, a group of aggressive soldiers will be waiting. Climb up and enter the code on the door 2603. Immediately deal with the rats. You can go forward or inspect the side rooms for supplies, mainly bandages, medkits, and anti-radiation drugs. Walking to the end of the side corridor, you will see a cutscene. Soldiers attack an unknown man. He asks for help to start the device, and you need to make a choice. We helped. Watch the beautiful effect of the device, after which the unknown man will disappear. Continue down the corridor.
You can find a cool suit here, so don't rush. On the right, there will be a room with acid fumes. Enter it and notice the breach in the wall leading to the adjacent room. Run past the acid and you will find yourself in another anomaly where floating glass will constantly cut you. On the left, there are cabinets. If you jump there, you will see a red hazmat suit — excellent gear. Then just open the door nearby and exit back into the corridor.
Move along the only path until you jump into the sewer. Walk forward through the old pipe and you will meet the unknown person again. After a short dialogue, move straight through another pipe. This way, you will reach the surface. Return to Star to tell him about his people and hand over the documents. After receiving the reward, follow the objective marker to the Junkyard.