Serpent's Bones Fortress (2019)

Publisher's blurb:

Built into a bone-dry canyon, this desert fortress is defended by murder holes and sharpened stakes—promising death to those foolish enough to attempt to breach the walls.

Reinforced gates bar both entrances to a ground-floor court,

and stairs lead upwards to a second-story rampart, stocked with supplies. High towers lead to simple, yet comfortable, chambers for a handful of people.

Four towers overlook the rest of the canyon, on the third floor. In one of them is a table piled high with gold coins, and dispersed within the other chambers are desks with papers, and beds.