From publisher blurb: "In the middle of a wide expanse of flat grassland, a lone barrow of earth and stone sits like a blister on the landscape. Even at a distance, a faint malevolence can be felt. Horses, pets and other animals will be uneasy within half a mile of it, and at night, eerie ghost lights can sometimes be seen atop the unnatural hill." 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.