Hindsight, Part 1

From the introduction:

Hindsight is an adventure...first run at Origins 2000.

The magistrates are asked by the Dragon Clan to investigate into the murder of Togashi Nobue, an ise zumi who was last seen alive on the Island of Silk. Once there, they are hassled by an irritable Mantis of the Storm Legion before getting down to business. They find evidence that the victim was actually the third in a series of ise zumi troubleshooters who came to the islands, working under the cover story of educating the populace in Shintao. The first two monks disappeared, but left clues for their successors in the form of coded Shinseist doctrine, which leads the characters to the ruins of Kyuden Gusai. There, they find Nobue's notes.