Military action
You've entered the Well of Dragons disguised as Cult of the Dragon members. So far you've managed to bluff your way past one patrol to make to the main treasure horde where you dispatched the guards and helped yourself to a few things. But now you have to figure out where the ritual is taking place so you can stop it before it's too late you end up having to face off with Tiamat Herself!
Continuing past the treasure chambers the sounds of the Draakhorn become increasingly louder until you reach a point where the sound waves are actually so strong that you have to force you way the last twenty or so feet down the tunnel into another large chamber.
After the din of the tunnel, this chamber seems preternaturally silent — until you realize you are completely deafened in the presence of the fearsome Draakhorn. Carved from the massive horn of an ancient red dragon, it hangs suspended by chains from the ceiling of this chamber, blasted with fire to a dark ebony hue and bound by thick bands of bronze. Draconic runes etched into its surface glow with a purple eldritch fire.
An air elemental sounds the Draakhorn with its endless breath while a stone golem stands guard. Not wanting to interrupt the sound immediate for fear of it alerting additional guards, you attack only the golem, dispatching it fairly quickly. As all of you are deafened by the sound of the Draakhorn, Malice attempts to motion everyone out of the chamber, unfortunately Pubert’s sidekick wolf, Taru attacks the air elemental causing it to stop sounding the horn. Even though you slay the elemental quickly and the Draakhorn is silenced, your deafness continues so you choose to lay in wait for a bit to see if anyone comes to investigate.
Sure enough, almost as the effects of the deafness wears off you hear the unmistakable sounds of a unit of guards rushing down the tunnel toward the Draakhorn chamber, so you spread out and wait for them to come rushing in. A squad of several Dragonwings, a Dragonfang, and a Dragonsoul burst into the chamber. You deal with them in short order but not before the effects of having gone through two battles so close together forces you to make the choice to rest here for some time before moving on despite knowing the ritual is still being cast and time is not on your side unless you feel like fighting a goddess.