From publisher blurb:
Mini-Dungeon adventure for 5 characters of level 4
On their way to another adventure, the adventurers chance upon a serpentfolk war hulk adrift on the Astral Sea. Characters recall that such hulks are powered by phylactery drives: engines that harness the essence of a disembodied lich to propel the hulk across the multiverse. Discovering a hulk that has been abandoned—as this one appears to be—is either a stroke of incredible luck or a sign of ill fortune.
Unbeknownst to the party, this war hulk’s phylactery drive contains not just any lich, but a legendary sorcerer king of old. Recently, the lich discovered a way to wrest control of the hulk from his captors. The lich awaits a band of unwitting adventurers to release him from his prison.