This is my favorite 3.0 edition module EVER. Simply amazing - it's a 'dungeon crawl' in the highest tradition of the old 1st edition classics like the D1-3 series, but it also shows just why those old-school dungeon crawls could be so much fun!
The players find holy shrines and a tomb for an order of holy knights that have been desecrated and infested by an evil. Curiously, the evil forces within the sprawling network of caves are competing against each other for a source of vast power - a power that the last remnant of the forces of the holy order is seeking to protect.
What's very interesting about this module is that it does provide some great roleplaying opportunities as players may find themselves embroiled in the politics of the different factions, or at least trying to prevent the factions from uniting against them as they make their way down to discover the surprises in store for them.
Another trademark of Necromancer Games' modules is that there are forces within the dungeon that the player characters simply cannot defeat or destroy by brute force. If your players try to treat it as pure hack and slash, they will be clobbered. They'll need to avoid some of the nastier encounters through stealth, trickery, or negotiation.
The module has a fairly epic-feeling ending, and enough adventure to make it something of a mini-campaign on it's own.