The Wax King, Book One: The Deathtaker's Daughter:

As the only deathtaker in the capital city of Belledon, Berol Lackey is kept quite busy preparing the deceased for burial. That is, until her eccentric friend, Joanne Menker, is discovered sitting in her own window ... dead.

Things become stranger still when Berol meets an old purple-robed wizard on his way to speak with the king about a plague that is destroying entire towns. Consequently, at her king's command, Berol finds herself traveling with the wizard on a quest to discover the cause...