I think I broke the game...
or can't see something ridiculously obvious.

Question is: Is there way to get at Mantle Cavern Two from Mantle Cavern One?

Every time I try to enter Mantle Cavern from Menzoberranzan overview map I end up at Mantle Cavern One.
As result I can't find golden necklace, give to Jarlaxle to make drow patrol to show up.
I am stuck (and yes, I've read cluebook)

I started to suspect that I broke some sequence of events after I visited first time Bazaar merchant Galentha offered me a SECOND trade option (not the first) - only Music Box (without candles) for Helm.

Maybe there is way to get at Mantle Cavern Two level from Menzoberranzan overview map?
Any suggestions?

Okey, never mind.
I spent few hours of searching...
And when I decided to post this question I found a solution in 5 minutes.

Apparently there is a mistake in manual.

At page 27 there is the Menzoberranzan City Interface.

So in the top right corner there is square named "Mantle Cavern Two"
BUT! in the game pushing this you will end up at Mantle Cavern ONE"

I didn't even consider to click on square in TOP LEFT corner,
which was named "Mantle Cavern one" in manual.

Solved.
As I predicted that was "something ridiculously obvious".