Dig deep in the Muck, where all the garbage of Lion's Arch flows.

The ghost that you require to talk to will be found deep in the sewers that run under Lion's Arch. Find the docks in Lion's Arc, jump into the water and you will find a tunnel that leads you underneath the city. Follow the following video to help guide you in the tunnels.

Related Videos:
Mad Memoires Site 2
Search the dead streets and forgotten thoroughfares of another Lion's Arch.
Mad Memoires Site 3
Say more now and look more where Kryta's descendants are buried.