The Shattered Mask (Forgotten Realms: Sembia series, Book 3)

The matriarch of the Uskevren family swears revenge for the murder of a loved one.

In her anger, she has forgotten one thing:
In the world of intrigue and deception, of shadows and lies that is Sembia, nothing is ever what it seems. An angry wizard with a lust for power can alter reality and distort the truth on a whim. When he is bent on treachery, murder and destruction can shatter an entire world.