Event on Colossal Cavern

The huge cavern open in front of you is lit by the glow of a phosphorescent blue-green algae. Other than the short path in front of you, the swampy turf will make for slow going for any but an accomplished Pathfinder. You can see a river ahead, but no obvious way of crossing it. (And speaking of crosses, you are still trying to discern the significance of the Templar cross at the entrance.) Onward! Through the Bog!