The Death Knight's Tomb

This dungeon is suitable as a one-shot or drop-in for characters between levels 12 and 17.

Taken from the Against the Idol of the Sun high-level hexcrawl campaign, the Death Knight's Tomb is a location-based exploration adventure. It features increasing localized time distortions that ultimately pit the party in a fight against an ogre Death Knight and his minions who just destroyed an elven time lab over ten millenia ago, which is just a few seconds ago in relative terms at the bottom level.

There are six distinct sections to the dungeon containing four combat encounters of increasing difficulty.
As written, the party enters the structure to rescue an overly adventurous Scorpionfolk couple and their rescuers, but they can be omitted or rewritten to any other species.