You follow the blue flowing river a little further until it forks. Off to the right, only a tiny rivulet stream flows, and the cave is mostly mud as it heads off into darkness. You see human boot prints in the mud heading off in that direction, which you can only assume belong to Fingus and Battrus.
To your left, the majority of the deep blue river flows downhill, but you could follow it along the banks and the large stones. Deep down that way to your left, out of sight, you hear what appears to be a man screaming in pain. The sound carries well along the water.
The golden box which you have been ignoring for some time now begins to glow strongly and pulsate.