Arrived at Zion, killed all the folks who attacked me. Got slightly confused when one of the guys had a "unique" name (Follows-Chalk). But I went on, didn't want to break the immersion by googling everytime something seems unclear. Turns out I accidentally must have hit someone I shouldn't have because now the WHOLE FREAKING ADDON just won't happen for me. I honestly don't know when and where this could happen. I'm mostly into close combat (I don't snipe everything away that moves) so I'm pretty sure I only attack the hostile folks. Some of the guys were shooting at me without an easy path between us so I had to take those out by shooting back at them. Maybe then I hit something I didn't know of. Well, those things can happen, but WHY did they make it sooooooooo easy to fail the whole thing?!? I don't have any previous saves so I'd have to start again from the very beginning but now I'm just tired of New Vegas and most certainly won't ever play it again. (I played New Vegas months ago and now had started it again only because I recently bought the ultimate edition and wanted to experience the addons. Yay!) I'm in such a bad mood I made an account so I could whine about this. If by accident any of the developers reads this: You did BAAAAD! Please growl "I'm BADMAN!". Thank you.

You are not the first person to do this. I'm sure it says you failed a couple of quests when you do that though. In this forum it has become a running joke that Follows-Chalk shooting causes people to fail the entire DLC. Hope you had a save before the DLC. If not, you should start making some. Sometimes the game glitches and you need to get out of the dlc. Sometimes you do things like this.

Welcome to the I killed Follows-Chalk club.

Well this right here's your problem.

I am not in that club Of course being a PC player not afraid of spoilers, i knew to avoid that

The lesson here is: know what you're shooting before shooting it.

Well, that doesn't make much sense, if you reach a close distance of Follows-Chalk then he will initiate dialogue with you after he's sneak killed a White Leg.
This is your own fault though, not the developers, you went in too hot headed and just started murdering left and right without consideration.
And when you do kill Follows-Chalk you will get a text saying QUEST FAILED: [Quest name here], so that should have been a hint that something went wrong.
Follows Chalk is also dressed vastly differently than the White Legs.
Finally, use VATS as a scanner to see what is hostile and what isn't before you open fire.


So again, the fault is not on the developers part, it's on yours.
You didn't save often enough (which you should) and you killed without thought (which you shouldn't).

There should have been an auto-save once you arrived in Zion, so simply swallow your pride, die and reload. Just don't make the same mistake twice.

This is still going on, since the release of this DLC to present day Follows-Chalk still continues being slaughtered by uninformed players, I feel so sorry for him.

This completely.

Never did it because I knew to look out for it.