The Dragon's Gullet

From publisher blurb: River trade between Farholme and Nordskamp depends on the working operation of the Dragon’s Gullet, an old water lock system built by dwarves. The Gilded Spear, an adventuring group claimed the ancient complex has been cleared of danger and an expedition was sent to inhabit and operate the water lock system. Your party is hired as extra muscle to protect the first river trade boat set for departure downstream. An easy job….right? An adventure for Levels 2-5 using For Gold & Glory ruleset--easy to convert to Old-school adventures.