Shadows of the Last War, Eberron adventure for D&D 3rd/3.5th ed, by Keith Baker.
“The ruined House Cannith citadel of Whitehearth holds the key to constructing a terrible magic weapon. Agents of the Emerald Claw will stop at nothing to recover the ancient device. As malevolent forces hunt for the artifact, rescourceful heroes battle the perils of the Mournland to reach Whitehearth first and discover the secrets that lie within.
Shadows of the Last War is a stand-alone adventure for the Dungeons & Dragons game that will immerse your characters in the Eberron campaign setting. Designed to challenge 2nd-level D&D heroes, it pits them against one of Eberron’s most nefarious organisations.”