From publisher blurb:
"About a half mile off a less-traveled road sits an old mill. The style is typical for the region, though it looks as if it has been unused for more than fifty years. Even the old brook that used to turn the large mill wheel has mostly dried up, and this may have been what caused it to be abandoned.
The creek in front of the mill still runs down from the distant hills, and is crossed by a wide, sod-covered bridge that looks functional. The water continues down to the road where it runs along it for a few hundred yards before feeding into a low gully and spilling into a deep ravine.
The remnants of a sign near the road are the only indication that the mill exists, though the original name is no longer legible. Just beyond the shrubs and brambles at the edge of the roadside is the stone-lined foot path that leads up the hill to the abandoned mill."
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.