The Ashford family archive occupied a climate-controlled room in the basement of the family estate an hour outside the city, a space Lucien had visited perhaps twice in his adult life, both times for reasons that had nothing to do with the boxes of genealogical records lining its walls.

"If there's precedent," his father had said, handing over the key with visibly reluctant hope, "it will be here. Two hundred years of Ashford marriages, deaths, and diaries. I never had the stomach to go looking for it myself. Perhaps you'll have better luck than I did."

They spent the better part of a day working through generations of family history,...