From publisher blurb:
A one-shot introductory fantasy adventure of inter-dimensional dread on the high seas for the fifth edition of the world’s greatest roleplaying game -
A galleon ferrying dozens of sick souls to coastal sanitarium vanishes without a trace. Some say she was struck by an iceberg. Others say sea raiders sunk her. But the truth is more terrible than either conjecture - something you will learn if you dare to board The Wreck of the Mother’s Mercy and dive into the black depths beneath her. Featuring new items and locations that can be added to any campaign setting, this adventure is suitable for a party of three to six, level one to three adventurers. Plunder the galleon’s wreckage and brave the cosmic horror that killed everyone aboard.