The Throne of Skulls

From publisher blurb: This is an OSRIC adventure for characters of 10th level and up. While exploring the hills far away from town the adventurers stumble upon a secret hideaway with an unusual and terrifying design. It is shaped like a giant skull. Who might live in such a place? And why is it so far away from civilization? Could it be the home of the fabled Throne of Skulls? The Throne has long been known to be an artifact of great power and great evil. A person in possession of it is said to be nearly invincible.