"Sixteen years passed since Nightless City...." Since the day he watched Wei Wuxian fall out of sight. He was in seclusion for part of that as he healed but he remembers how difficult those years were. Playing inquiry in the thought he might be able to contact the wandering soul. Searching the Burial Mounds for any sign of the body. And then the following years which were spent simply trying to move on.

Sixteen years before they uncover the truth behind everything.