START
After Alisha tips you off to the secret ruins in Lakehaven Heights when you reunite at the Griflet Bridge, head back to Elysia. Sorey and Mikleo make introductions at Gramps’ House, and you can return Gramps’ Pipe if you have it. Gramps and Lailah will have a quiet conversation, and when you decide to leave the party will regroup. This event is only available before Mayvin reveals the Earthen Historia he keeps to the party in Lohgrin.
After defeating Cerberus in Elysia, head to Gramps’ House and inspect the bookshelf to discover Gramps’ Letter (and Gramps’ Pipe, if you gave it back to Gramps earlier).