Hidden cave

You need to find the location of Stargazer's hidden cave in Undiscovered Land.
==Walkthrough==
Head towards the Undiscovered Land. The hideout is not marked on your map, and is located in the [ NW corner of the location]. You will not be able to enter yet due to the teleportation disable being delayed, but the quest will technically be marked as complete after discovering the cave.
After that, Marked One will message Fang, telling him about the hidden cave existence, that somebody's inside, and that the entrance is still blocked. Fang will warn him to not enter - whether it's Skygazer or not, it could be dangerous. Fang invites him to the [ Fiery Cave] to discuss it.
== After the quest ==
=== Talk to Fang ===
Go to the [ swamp] and enter the Fiery Cave through the top entrance. Additionally to the usual frogs in the swamp, a large contingent of zombies has populated the entryway, at least two of them are exploders. Zombies spawn as you approach the entrance from outside; try throwing some grenades into it before entering.
Make your way inside the cave and talk to Fang, handing him the dossier on Stargazer. He will say that the key to the hideout was probably planted for you to discover, and all this could be a trap, but you should try nonetheless. He agrees to stay as a lookout once you reach Skygazer's hideout.
After the talk, a large pack of mutated cats will be running around the main exit of the Fiery Cave.
=== At the hideout ===
Escort Fang to the hidden cave. Enter it while he's watching your back. In the cave, you don't find any traces of Skygazer, but there's a teenage girl named Fly who refuses to talk until you find her doll. Pick up the loot in the empty chamber next to Fly and leave the cave.
A helicopter will arrive carrying both Skygazer and Panther. Speak to her. Turns out it was a setup all the way back to the Warlab, and they worked together to get the shard of the Monolith that Fly stole, and used you to find it and make contact to Black Doctor who is their rival. Kolmogor isn't her brother either.
Talk to Fang. Escort both him and Fly back to the loners' camp; Fang will babysit her for now. As you walk, there's some message exchange between Marked One and Panther, in which she says that there's no C-Consciousness and no Black Doctor at all.
Upon arriving to the stalker camp, Strelok decides to go to Warlab to check up on Klyonov's progress with the artificial Poltergeist's Heart, starting Klyonov's artifacts. Before you leave, Fang messages you to talk to Fly. 
Fly says that her parents used to work in X-10. She managed to make her grandfather, a military general, organize a helicopter flight into the Zone to visit their old house at Radar, but the helicopter has been shot down. She wants you to bring back her doll from the old house in the task Fly's doll.
Talk to Fang once again before leaving.
==Notes==
* Unlike your other meetings with Fang in the cave, you cannot simply jump up through the gap as there's an invisible trigger that needs to be hit in the swamp entrance. The part of the cave that contains the zombies spawns an immobile sentient burner once you step into it. This burner is normally killed by players dropping grenades down the entrance to the cave. Unless it is killed, Fang will not speak his quest dialogue.
** You can still enter through the "easy" entrance if you jump through the gap in the floor, but you will need to step into the zombie section and kill the burner. Be warned as it spawns directly behind you if you are coming from that direction and can easily kill you in the enclosed space if you aren't aware. After this you can kill the zombies without fear of aggroing Chimera's camp.
* Do not jump into Old-timer's teleport to Shura the Gynecologist's cave after picking up Fang from the Fiery Cave. This will cause him to lose his pathing and sit still like an idiot, and you need him to be there for the story triggers.
* Fang is invincible, but makes up for it by being very, very dumb. He will chase a single mutant all the way across the map, pulling several camps and wasting untold amounts of time, so it's best to clear out the path to the hidden cave before meeting up with him.
* The helicopter will not land unless both you and Fang are in position to avoid softlocks. If it continues to turn without landing, approach closer to Fang to trigger the landing.
==Bugs==