From publisher blurb:
Introducing Drop-In Dungeons! This series of releases will feature small adventures and dungeons, generally 5 pages or less, that are effortlessly inserted into almost any campaign for the times your players zig instead of zag, and you find yourself unprepared. With the loose and opened ended way Drop-In Dungeons are written, you (the GM) can bait the hook however you want; the appetizers and desssert are up to you, herein you'll find the meat and potatoes.
The Missing Heroes: The dwarven outpost of Bul-Nor was originally built well over a thousand years ago as a holy site for performing funeral rites. The bodies of the dead were dropped into a pit at the end of the ceremonies, where the bodies would be disposed of by beasts. As this practice became less and less common, the outpost was eventually abandoned. Over the years it has been used as a lair by many creatures, but most recently it has become home to not only a small band of goblins, but to a spined devil that has convinced the goblins to carry out his bidding. Intended for a tier 1 group.