One of the most popular 90 minute adventures I ran this year is based on an episode from the 10th season of Stargate. It’s fun, fast and can work in almost any setting. Because of this, I’ll present it in the most generic terms possible, leaving it up to you to decide if the puzzles the PCs face are technological, divine, or magical.
The PCs are hunting for a holy grail of some sort. They can be Arthurian knights looking for the literal holy grail, Jedi knights searching for a holocron in the tomb of an ancient force user, or archeologists searching for the lost treasure of a Mayan god in a hidden temple in Peru.
In any case, begin the adventure by giving the PCs the following handout:
“Only those of virtue true may win the prize concealed beyond the reach of the flawed and tainted. The holy grail shall belong to he who speaks the guardian's name. The true man will look with prudence, wisdom, kindness, charity, and faith. Be the truest of hearts and ye shall find the answer.”
While it’s possible to place the quest in a totally isolated area such as a desert shrine or a toxic planet abandoned millenia ago (add killer ants for that special “go away” feel), I enjoy running it the most when there is a community nearby. While this runs the risk of prolonging the adventure as PCs become involved with the locals, this offers some advantages:
This is a very deadly adventure. New characters can be recruited from the settlement, either in the form of ambitious locals or newcomers looking for the same prize.
If the PCs lack some vital items or abilities, these may be procured in the settlement. This is especially important for the Test of Kindness (see below).
An opportunity to roleplay. Again, this may make the game a little longer but also make it more memorable. In the end of the day, no man is an island and we can only assume the same is true for elves, orces, killer ants, and forsaken Jedi.
So unless it’s vital for you to complete it in exactly 90 minutes, I recommend placing some nice little town or community near the testing grounds, possibly risen to service the seekers. If you want it to be extra helpful, make it a scholarly or monastic community dedicated to the mystery of the holy grail. If you want to make it more memorable, make it totally alien, such as a community of stone giants who believe all newcomers are just dreams or insectile aliens who can barely understand what these crazy primates want from them.
After the PCs have had time to study the scroll, scout the area and chat with the locals, it’s time to start the real adventure. It includes five tests: two outside the location, let us call it “temple” and three inside. Each test represents one of the virtues as the ancient builders understood them:
The Test of Prudence
Adventurers from various historical periods, maybe even different worlds, are held in place by an invisible force. Some look concerned, some look terrified, but most look like they were just taking their evening constitutional when time froze all around them. Anyone who tries to touch a frozen person becomes frozen as well.
The test is an invisible labyrinth made of time-stopping walls. Anyone who touches a wall becomes frozen in time forever. PCs can pass through this labyrinth either by throwing small objects in front of them to reveal the invisible walls, or by casting a detection spell of some kind/ using temporal measuring technology.
Be advised that if you allow the release of frozen PCs, the players may decide to release some hapless NPCs as well. These may just run away screaming, become allies, or attack the PCs, either driven insane by their long temporal stasis or just looking to get rid of the competition. Make sure to have some nice NPCs handy if you decide to go that route.
The Test of Charity
The PCs find a gorgeous chest in a clearing before the entrance to the temple. The chest is surrounded by ancient skeletons and some interesting items that have survived the ravages of time. If they open the chest or pick up any of the items, they instantly become trapped by an impenetrable force field. The chest itself is empty. Moving the chest won’t move the force field.
To solve this test, the PCs must place inside the chest items of greater value than the ones they’ve taken from the area. If they’ve taken nothing, putting literally anything inside the chest and closing it should do the trick.
Note that the bubble is invisible. The only way to discover it’s gone is by prodding it.
The Test of Kindness
The PCs enter the temple and face a crossroad. To the left they hear dripping water. To the right they hear a crying baby. If they turn left, they find a large underground lake fading into darkness. While looking normal (but smelling awful) the lake is actually a huge reservoir of deadly acid that leads nowhere. Sailing it is not recommended.
If they turn right, they find a baby in a crib inside a cage. To solve this test, the PCs must really help the abandoned baby. Simply breaking it out of the cage is not enough.
The baby is starved and dirty, but otherwise unharmed. The PCs can either take it to the settlement, teleport it to a safe spot, or do some other action that will insure the baby will have a loving home. Leaving it outside in the woods definitely won’t work.
Since this is a short adventure, assume that just about any couple would love, just love, to adopt this baby. You don’t want to turn your adventure into a bad rom-com. Or maybe you do. Just don’t expect this to be over in 90 minutes then.
The Test of Wisdom
After the PCs take care of the baby, they will find the wall behind the crib gone, revealing a chamber with two riddles inscribed on opposing walls. Under each riddle there’s a small alcove. On the third wall there’s a text without an alcove underneath: “the words of the wise are heard in peace.”
In order to solve this test, the PCs must place inside the alcoves items that answer their respective riddles. I like using these two:
I have cities without people, forests without trees, rivers without water.
I'm the eye in the blue face. I feed the world. If I go blind, the world will go blind as well.
Answer: sun, can be solved by a flashlight, some kind of light spell, or even a drawing of the sun.
The Test of Faith
As soon as the correct item is placed in each alcove, the wall with the hint slides open to reveal a corridor engulfed in terrible flames that cannot be quenched. After the flames there’s an abyss peppered with the bones and broken items of those who tried to cross it but slipped and fell to their deaths.
Both the flames and the abyss are perfectly safe. The flames retreat if someone walks into them. The abyss is actually crossed by an invisible bridge. If you’re running a fantasy game, both radiate magic but its type cannot be detected.
The only way to reach the final stage is to use the bridge. If the PCs cross the abyss some other way: flying, using ropes, teleportation, jumping like Wonder Woman, etc… they just find a hard wall on the other side. Only faith opens the way to the holy grail.
If you only have a few minutes left, then this is it. The PCs enter a magnificent chamber with the holy grail waiting for them on a pedestal. Hooray! Time to go back to town, have a pint and pretend like PTSD is not a thing.
However, if you still have some time left to burn, then there’s a dragon/ giant robot/ bone colossus/ fallen angel/ ancient ghost guarding the holy grail. The PCs can deal with it in the old fashioned way -- by beating it to death -- or by saying the name of the guardian, in which case it will take a step back and let them snatch the prize. Hooray! Time to go back to town, have a pint and make sure no one sees you cry.