The Lamenting Lighthouse is a four-hour adventure for 5th-10th level characters, designed for Dungeons & Dragons 5th Edition, with a nautical theme, heavy undead and horror elements, and mysteries to solve! One lonely lighthouse shines the way through the rocks and shoals that deny entry to the northern Moonshae Isles. But when the party’s transport approaches, a horrific gale at their backs - no light is in sight... The party must venture ahead of their vessel in a race against the storm to the restore the beacon before their ship is lost. What has befallen the keepers, and what dark secret does the lighthouse hold? Will the heroes prevail, or will they join the lighthouse's lament? This adventure can easily be inserted into a run-through of Ghosts of Saltmarsh. This one-shot can also serve as a nautical interlude in any on-going campaign where the characters have to take to the sea. Included with this adventure are: + 6 original custom creatures, the dread wraith, the dread wight, the swarm of seagulls, the captain, the rating, and the sailor + 12 player hand-outs with notes that shed light on the mystery of the lamenting lighthouse, with a randomization mechanic that ensures a degree of replayability + 9 original fleshed out NPCs, including personality traits and roleplaying tips + 2 original magical artifacts + 7 hand-drawn maps of important locations + a story reward and 2 story hooks for continuing the adventure (depending on how the adventure resolves)