The Final Puzzle

The door from the chamber opened into an unlit hall. We carefully proceed about 50' down the hallway when it opens into a small chamber with a stone door on the opposite side. The door is flanked by pressure plates with the number 4 engraved on the wall above them. There's a flowing fountain in the center of the room with three jugs on the fountain ledge. Each jug has a number inscribed upon it and are different sizes. One jug is 3, the next is 5 and the last is 8. The party quickly deduces that the pressure plates must each have 4 units of water in the jugs to open the door. Believing they figured this out that easily, the part poured approximately have the water from the jug marked 8 into the jug marked 5. This did trigger the pressure plates, but they immediately reset and the fountain started to spew more water than it was taking back up and the entryway the party entered through sealed behind them. Jade came up with the idea to empty one of their waterskins and use it to hold exactly 4 units of water by filling the jug marked 5, draining that into the jug marked 5, then that into the jug marked 3. This left exactly 2 units in the jug marked 5, which was then placed into a waterskin. Doing this twice left them with 4 units of water in the wineskin. Repeating the process yielded 2 waterskins with exactly 4 units of water. Emptying the waterskins into the jugs marked 5 and 8, then placing those jugs on the pressure plate yielded no result. Clearly, this was a magical puzzle that required the use of only the three jugs to achieve exactly 4 units of water in two of the jugs. After attempting iterations for over 45 minutes, Bob eventually stumbled upon the correct pattern of pouring water between the jugs. Bob hadn't even realized he solved it and was about to make an incorrect pour when Thomas realized what Bob had done, stopped Bob and pointed him to the correct pour. When the two jugs with exactly 4 units of water in them were placed on the pressure plates, the door opened, the fountain began to flow at a normal rate again and the water drained out of the room, through the newly opened door.
 
The party listened carefully at the darkened doorway and could detect the sound of hoarse breathe. No longer having a lit torch, the party decided to let Jade with darkvision stealth her way into the room and determine what lay within. Whether magically cloaked, or Jade being careless, she accidentally stumbled into something very large and scaly. At that moment, a deep, bellowing voice was heard asking "Who goes?". The remainder of the party enters the chamber as Jade answers the question. Shortly after entering the room, a small beam of purplish daylight could be seen entering the chamber from above, apparently from a hole in the chamber's ceiling to allow the light in. A chair with a book could now be seen in the chamber. On the floor, encircling the chair were arcane runes. The party could now also see that the breathing and the bellowing voice belonged to an ancient gold dragon. This dragon made the green dragon the party slayed in the Dwarven Isles look like a baby. It was clear, this dragon would make quick work of our heroes if that were his choice. Conversation with the dragon reveals that he is aware of what is happening in the world and knows what is still to happen. He states that he has been waiting for a long time for someone to come here and claim the treasures - the book and chair. He also informs them that there is still time to save the world but what is about to happen next cannot be stopped. To save the world, the party needs to use the chair and the manual upon it to get off of this planet as that is the only way the world can be saved. He tells them that they must find Captain Harry to help them do this. Thomas makes his way to the chair and picks up the book. Below the book is a coin purse containing the magical coins used as currency in the Diner at the Edge of the Universe, but this time they are black in stead of red or purple. Just as this happens, the light from the hole in the ceiling begins to fade, the dragon tells the party to enter the circle on the floor and begins casting a spell. A sensation of weightlessness and an instant of utter blackness is felt.