The Restless Ghost/Quick guide

Getting started

 * Talk to Father Aereck in Lumbridge church.
 * Go through the graveyard's Southern exit and follow the shore to a mining site. Head west to a hut in the swamp.

Ghostspeak Amulet

 * Talk to Father Urhney inside the hut.
 * Go back to the graveyard and open a coffin located south of the catacombs.
 * Equip the Ghostspeak amulet and talk to the ghost.

The Skull

 * Head back through the southern gate of the graveyard, keep walking until you reach the mining site once again.
 * Look south-east of the mining site, there will be a large rock.
 * Search the rock, you will receive a muddy skull.
 * Kill the skeleton OR run away.
 * Go back to the graveyard and use the skull on the coffin.
 * Quest completed!