The hot springs are not just hot, they're scalding! You can feel the heat raising up as you approach. A cool source of water pours in from what you guess is a nearby river outside, hits the hot rocks, likely from a lava flow near the surface, and boils within moments. People have large stone basins that they lower in, then pull away and allow some time to cool before using the water for drinking, bathing, cleaning, just about anything.
Looking at the basins gives you an idea. The hot spring is set up fairly high along the cavern wall, with a relatively narrow channel just below it. You confer with the Princess, who becomes very excited by your idea. They gather up the basins and sink them into the springs, with cords attached to each and running over the narrow channel where several men grab hold and hide.
You and the Princess then move up to the front lines to direct them. Upon hearing the plan, they are emboldened, and feel more ready to take on the lizards.
And just in time! As you and the Princess are at the third gate explaining the plan, the first one is ripped open by an explosion. You and the soldiers rush over to help with the surge of lizards that now pour through.
The fighting is intense, but with your help, you manage to hold back the first wave, giving up little the ground. The survivors of earlier battles know from experience that the Big One tends to appear after two waves. With the second wave, the men begin to give up ground, fighting conservatively, not risking as much as they would have without a plan. Those closer to the hot springs begin giving up the most ground, and the line begins to swell at this point. You are among these men.
When the Big One finally does appear, you cannot help but feel afraid at the massive power of the creature, including its surprising apathy toward the other lizards, as it tramples several coming through the entrance. Scanning the battle line, it spots the thin spot where you are and charges forward. It moves astonishing quickly for its size, and your group breaks into a run. That was not part of the plan, but if you all die before the Big One reaches the hot springs, the plan may not work.
The Big One smashes through the battle lines, knocking over man and lizard alike. The men on the fighting lines redouble their efforts and are joined by those who were hiding and quickly close up the gap, though the fighting remains furious.
Along the path to the hot springs you can hear the heavy stamping of the Big One as it moves up behind you. The man running to your left suddenly disappears. All you hear is a soft yelp behind you and the heavy foot falls slowing down for a second. The hot springs seem impossibly far away suddenly, but rounding the corner you spot them and lean into the run. Another man disappears as you race around the corner. You can now feel the heat coming from the rock to your right. The hot springs are now above you, full of hot, boiling water for the next fifteen yards, and the lizard is right behind you.
Passing beneath the ropes, you give a cry and the men stand and pull hard. The stone basins , full of boiling hot water tip up over the side and fall down on the Big One, dumping their contents on the lizard. It paused when seeing the men stand, giving them just enough time to seriously scald the creature all over. To say nothing of the damage caused by dropping heavy stone basins on it.
The Big One lets out a roar at the men above it. You stop and turn, seeing the opportunity. It's blind in its right eye, and looking up to its left, it can no longer see you. You charge forward with the spear and stab it in its lame eye, piercing through to its brain, killing it.
The men above you cheer, then race over to the lines to finish pushing back the invasion. You will later find out that upon hearing the roar, the rest of the lizards somehow knew their leader was lost, and retreated back into the tunnels beyond the chamber.
You suddenly feel exhausted, as the adrenaline of the race and the killing blow now drains away and you slump against the cool wall opposite the springs. A few minutes later, when the battle is done, the Princess and guards appear, celebrating the victory and your bravery.
A feast is held, featuring the moss, which is edible but not especially tasty, and lizard meat boiled in the hot springs. You're hungry enough to eat, but find yourself missing the protein bars you'd originally packed.
At the end of the feast, the princess presents you with several sparkly stones you'll later discover in the light to be uncut diamonds, then a parade is held to escort you back to the surface.
Near the entrance, nearly everyone stays back, as the sunlight is too bright for them. Only the Princess and the translator continue all the way to the cave entrance, and both have to turn their backs so as to not be blinded.
They both thank you again for helping to fulfill the prophesy of the war coming to an end. The princess gives you a hug, and at last you emerge in the sunlight, your eyes taking several long minutes to adjust.
You return home, uncertain of how to tell the story.
The End.