A letter written in an almost painfully precise hand by someone who signs off as "Calista Keen."
In it, she tells her parents in Praenost of her recent marriage to a man in Junoon. While it involves a lot of very dry description of the specifics of the ceremony and how she met her partner, it's clear from the tone that she's very happy indeed. She signs off by thanking her parents for raising her, and asking for the recipe for a certain cake.