Gates of the Eternal Serpent

Publishers' blurb:

Tucked away within this partially-eroded mountain lies an isle encircled by pillars and engraved with the ouroboros—a snake eating its own tail. It is nearly overgrown by wildflowers and verdant, green ferns.

An icy stream surrounds it, and beyond waits a worn stone gate, runes carved into its surface. Tunnels—many of them filled with water—break away from the main cavern, leading deeper into the mountain.

To enter this ancient place, you must first cross a steep, rocky gorge. Beyond that wait the statues of robed figures, holding swords and guarding the entrance.