From publisher blurb:
"Standing atop a low, flat hill is a cluster of irregularly carved standing stones. Seeing them silhouetted against the sky, they seem to have no rhyme or reason to them, but upon closer examination a pattern can be discerned.
The seven-foot-tall stones form a rough circle about sixty feet in diameter with rows of menhirs radiating ten yards out towards the cardinal directions. In the very center of the circle is a larger, rectangular stone in front of what looks to be a kind of deep well. The opening is roughly three feet in diameter and lined with cut stones. Peering into the well reveals nothing, but dropping in a light source will show that it descends for nearly a hundred feet to a dry bottom. Little else can be seen from the surface."
The purpose of these books is to help DMs put together an interesting encounter in a short time. Each Adventure Keys release does this by starting with a unique location that can be inserted seamlessly into an existing world with little or no modification. They are modular, with many options and variants available so that the DM can customize it to suit their needs.
There are six sections that include the Location, Hooks & Goals, Characters, Trappings, Threats, and Changes. All but the first have multiple options each, and since the DM isn’t limited to using only one option, the variations available are quite numerous. Sections can be used or ignored at the DM’s discretion, or even modified based on the situation or to scale its Challenge Rating.
The options are deliberately non-specific for ease of use. The DM can include them as they are, combine them, or use them for inspiration to create an entirely new options.