Now that the party has successfully entered the Citadel, by way of the hidden entrance into the Dormitory tower, they have one way to go: up.
To advance, they will need to solve a simple puzzle that involves ordering lunar phases in a certain sequence using a device on The Dias. Solving the puzzle will activate the central staircase.
REMINDER: Descriptive text from end of last section
You continue down the dark, rocky tunnel twisting this way and that. Everyone is aware of gradual upward progress, and a light source emanating from somewhere ahead. Finally, you encounter a stone door standing ajar. You pass through it into some sort of antechamber with a staircase leading up.
The staircase leads to a massive central hall - some sort of common area for acolytes. At the center of the room stands a prominent dias in front of a miraculous spiral staircase made of bright polished stone.
The markings along the floor of the hall are evidence of countless gatherings within its walls, from festival meals to times of great celebration, ceremonies and lessons. Along the rear wall of the hall, a gallery stands above behind a rail, for minstrels to fill the hall with sonorous sounds aided by the acoustics of its vaulted ceiling.
At this moment, the hall stands utterly still and silent–the songs of those past minstrels at past celebrations nothing but a pale memory.
The Gallery at the back of the hall stands 60 feet above the main floor, providing a good view of the whole chamber. This is a place where minstrels gather to perform music. Right now, it is empty of life and eerily quiet. Investigating this area reveals the following:
A few untouched violas lean against the railing. The violas have hidden magic. If a player with any musical training in their background touches one, they feel a sudden but pleasant tingle shoot up their arm. Playing a short song on either viola activates the following effect: Anyone within hearing range of the song gets darkvision and +1 to WIS checks for the next 30 minutes. Note that, because of the acoustic properties of the space, everyone in the main chamber would be in hearing range if the instrument was played from the gallery.
A wooden music stand has a picture scratched into it from something sharp (perhaps a dried up fountain pen?). The crude picture depicts line drawings of lunar phases arranged in order according to the Solution shown in Lunar Phases Puzzle. There is also a loose sheet of music, with part of a song making jokes about High Priestess Nerezza.
Looking at the main room from this vantage point makes it clear that the central dias is surrounded by large inscriptions on the tile floor. The inscriptions clearly resemble lunar phases. They are in order according to the Starting Position shown in Lunar Phases Puzzle, which does not match the picture carved into the music stand.
The dias rises 20 feet in the middle of the room. It can be accessed from any direction using one of four staircases. The design of the Dias channels foot traffic from these small surrounding staircases to the massive central spiral - a 200 foot staircase made of brilliant stone that seems to shine from within.
Access to the main spiral staircase is blocked by a golden gate. See The Staircase section below for more details.
The dias is decorated with a single platform positioned to address large crowds filling the stadium style seating in this main chamber. From this platform rises a distinct silver rod with an ornate device mounted on top.
Lunar Phases Puzzle
The ornate device on the dias resembles a miniature orrery. In the center is a large sphere with the symbol of Sel. It is surrounded by 8 smaller spheres made of an unidentifiable stone. It is a magical puzzle that unlocks the central staircase.
The sphere on the west side is locked in place, and shows a filled circle facing up (eg. full moon).
The sphere on the east side is also locked in place, and shows an empty circle facing up (eg. new moon).
The other 6 spheres are initially arranged to match the large inscriptions on the floor surrounding the dias. The initial arrangment is shown above in the Starting Position diagram.
The moment a player touches any sphere, a song starts echoing through the main hall from an unknown source. The longer the song plays the worse the player characters feel. If the song reaches the end before they have solved the puzzle, they all fall unconscious.
Anytime a player rotates a sphere to a new position, the corresponding inscription on the floor glows blue and magically rearranges itself to match the sphere. This is purely for visual effect.
The solution is to arrange the spheres according to the standard phases of the moon, as in the Solution shown above. The moment this order is in place the song stops playing, the golden gate slides open, and the magic blue light leaves the staircase and fills the inscriptions of the moon on the main floor.
Tips for running the puzzle:
You don’t have to play the recording of the magic song. You can simply describe what is happening and start a timer. Keep your players up to date on the progress. The goal here is to apply a sense of anxiety and urgency by adding a countdown to an otherwise simple puzzle.
Don’t let the players calmly solve the puzzle. Interject occasionally with descriptions of how the music is filling their heads, distracting them, and making them feel worse by the second. Make it clear that this song will have a very bad effect if they don’t hurry.
The solution to the puzzle is inscribed on the music stand on The Dias, as described above.
The solution to the puzzle is inscribed on the walls of the hidden tunnel the party entered through.
The solution to the puzzle can be intuited by anyone who understands the lunar cycle. Feel free to remind struggling players who would know this that they can make a Nature check to remember this.
The 200 foot high spiral staircase is the central visual feature of the main hall, and is the only way the party can access the higher levels of the Moonlight Citadel and continue their quest.
Access to the main spiral staircase is blocked by a golden gate. The steps are covered by a spectral blue light that resembles a slow-moving ghostly waterfall. A small creature or object could fit between the bars of the golden gate. Anything that touches the blue light will discover that it acts as a perfectly frictionless slide. Unless you can fly or remove the blue light, climbing this central stair is not possible while it glows.
Players can use the staircase only after solving the magical puzzle on The Dias. The puzzle is described in that section above.
Note for flying characters or other flying solutions
If your party can somehow fly, through magic or mechanical means, you can choose to barricade the top of the staircase with an impassable golden gate. You may also choose to simply let them skip this puzzle, as a reward for their earlier investment in flight mechanics.
Once they gain access, the players can freely climb the staircase. Narrate the enormity of the climb and continue to emphasize the unusual silence of the large hall. Anyone looking down will see the large lunar inscriptions glowing blue–a visually striking reminder of their victory over the puzzle.