How about
The Tangle of Repose (Look up the “angle of repose” if you don’t understand the reference.)
Under the Tipping Point
A Feather against the Tipping Point
The Tripping Point
J.
Damn you!
I came here to post something from that poem.
I was thinking “Two Paths Diverging”
If this is the first in a series(hope, hope) it could be subtitled “The Stony Path”
It is the first in the series. But I really want to stay away from blatant “Stone” puns (especially any that involve using a form of the word or as part of another word).
I’ve been brainstorming using urban fantasy words like “darkness/dark” and “shadow” and concepts like “brink,” “beneath/below,” “bridge,” “passage,” “decision point,” etc. Got a few I don’t completely hate, but I think the answer is still waiting for me out there somewhere.
Shadow Precipice?
The Lesser Evil
Easy Street, Dead End
Right Lane, Wrong Road
A Streetcar Named Demur
Stone of Sisyphus?
Edge of Allegiance
Verge Of Realms
Dimensions Divided
Between Light and Dark.
Paths Untravelled
The Narrowed Path
Fear of the Unknown
Would you all just stop. I have the perfect title.
“CASTING The First Stone.”
ffttt 
Another descriptive word that could be used is “cusp.”
On the Cusp
In the Balance
Between Two Shadows
Between the Shadows
A Choice of Shadows
Bleak and Fast
Californian Balls of Fire
Surfin’ Sea of Magic
and Couple of Stones
Stone and Glass
Stone the High (sorry could not help it)
Sixteen Stone, What D’you Get?
Shadow of the Valley.
Because the rich old lady makes me think about Miss Havershim, I’m going to suggest Mage Expectations.
ETA (and another word that means stone is Pip, right?)
Mage and minge.
Gift of the Mage
Valley of the Shadow