The restless ghost is a spirit haunting Lumbridge cemetery, much to the displeasure of the local priest Father Aereck. He was killed by a warlock while mining at the Lumbridge Swamp mine and was buried without his head. This caused him to become The Restless Ghost.
Eventually an adventurer got hold of a ghostspeak amulet and spoke to him. He explained what happened, and they went to retrieve his skull. The skull however was guarded by a skeleton warlock. Once his skull was retrieved, it was placed in his coffin and he faded away, finally at peace.
The restless ghost is summoned.