Shrine of the Earth Barons (5E)

From publisher blurb:

A 5th Edition Mini-Dungeon for 4-6 PCs of Levels 10-11

Followers of earth deities literally worship the ground they walk on and have always built below-ground shrines. A school of four gnome mages called the Earth Barons was no exception, constructing one such holy place where a desert met a range of rocky hills. Recently however, the mages were wiped out when a visiting dignitary turned out to be a suicide assassin that broke a fully-charged staff of power in their midst. The PCs find the unsealed capstone to the shrine as they are on another journey. The recent event isn’t yet common knowledge, and the temple is unused; therefore, despite the guardians, a brave party might be able to discover two valuable items.