AX5 Eyrie of the Dread Eye by Courtney Campbell. It's purely a site based adventure for levels 6-8 (ACKs or B/X), with no plot, but it does have a fairly detailed and interesting back story. The Dread Eye of the title is not a euphemism for the classic D&D beholder, but a strange demonic entity called the Occulus, who was summoned and imprisoned in a city long, long ago. The Occulus reminds me more than a bit of Yog-Sothoth from the Cthulhu mythos, as it's both a gateway and an entity. There also a few other Lovecraftian flavored encounters, such as proto-oozes and intelligent apes.
While the city has been ruined for a long time, it's still ripe for looting because of a combination of hazards and being off the beaten track. The module emphasizes that it should be a decent trek away from civilization, in this case, a borderlands style keep. That keep is not detailed — it refers to the excellent AX1: The Sinister Stone of Sakkara which does have a detailed breakdown of such a keep, but it does list a different set of NPCs that run the Keep. So you can just swap them in.
While the overland trek to the Eyrie is not overly detailed, it does have some special encounters: cannibalistic serpent worshiping giants, alcoholic manticores, sarcastic cave bears, and a roc named Mabel. Getting up the cliff to the eyrie is an adventure (and really a dungeon crawl) in of itself. It's somewhat linear, but interesting.
There's only 8 locations in the Eyrie itself, plus ten random ruins (just one location described each). Indeed, actually reaching the Eyrie is something of a letdown, because it's less exploration/adventuring and more dealing with the various factions. The factions are varied and creative, but also perhaps too weird for players to really show much interest in. There are hell wasps, fungal zombies, clockwork like people, intelligent apes, and basically walking stuffed dolls or scarecrows.
The only really sympathetic encounters are with a large intelligent wolf and its offspring, as well as a surprisingly friendly chaotic mage. His tower is the only location really detailed in the Eyrie.
Overall the monster variety in the module is excellent, including a lot of new ones. There's also a large amount of varied treasure, though like in most ACKS adventures, some consists or trade goods, basically.
The PDF is nice looking, with high quality color art by Dean Spencer and Eric Lofgren. The maps are isometric, which is something I don't like because they are often hard to use, but that's not actually the case here, they are quite legible and do a good job of comping with the 3d nature of the dungeon (essentially the way to the Eyrie)
Eyrie of the Dread Eye is really creative, but I think it sputters out at the end at the Eyrie. While it's pretty explicitly inspired by the classic I1 Dwellers of the Forbidden City, that had much more of the actual city described, and more easy to relate to factions. This details the journey a lot better, but requires the DM to flesh out the city in greater detail. Also left unaddressed is the consequences of the continued existance of the Occulus. It seems likely that most players would want to find a way to get rid of it.
But all in all, it's definitely worth checking out, especially for only $4.99