The Third Verse, by Johnstone Metzger & Tony Dowler

The Third Verse is the third of Johnstone Metzger's Dungeon World / Labyrinth Lord series, and like the previous adventures before this one the River Knife runs alongside the area where this module takes place. I think this is pretty cool because it allows a GM to use all of these adventures as part of a larger campaign and use the River Knife as a constant feature and returning point for the PCs. Either the river is their main method of navigation, or imagine a three-segment artifact that needs to be put together and each piece is found somewhere in all of the adventures. This isn't something that is suggested in any of these modules, it's just my own flight of fancy after having read all of them.

This module has the PCs being asked by a venerable sorceress to complete an ancient song that will banish the monsters the plague this region. There is a short description of the town of Springvale and the sorceress Liniakatra, and the rest of the adventure is a dungeoncrawl. The players presumably learn the first two verses from Liniakatra and then they must venture into the underground temple housing portals that spring forth a variety of monsters to learn the third verse and seal the infernal portals forever.

This is a fun adventure, but short. There are some interesting conundrums and encounters inside the dungeon itself, but some GMs might be turned off by the simple dungeon design. The whole structure of the dungeon and it's denizens reminded me very heavily of playing Gauntlet when I was younger, but it's different enough that most players might not notice the similarities. There is a lot information here to build off as well, with the portals that disgorge otherworldly monsters to the shrine in the last level.

You can purchase both pdf and print versions of "RK3 - The Third Verse" at DriveThruRPG or just a print version at Lulu
Johnstone Metzger also has a blog and a Patreon campaign for writing up monsters in Dungeon World and Labyrinth Lord stats
Tony Dowler also has a blog and a Patreon campaign for creating maps