In all worlds, in all times, there are hidden treasures. On the high seas, pirates buried their doubloons on lost islands. In a fantasy world there are dungeons, traps and deadly guardians. In a cyberpunk dystopia the megacorporations hide their secrets and money behind powerful encryption in high chrome skyscrapers.
In "X Marks the Spot" (a roleplaying game run in precisely two hours) the players seek a hidden treasure. The GM decides (or grabs a pre-made scenario from the book) what kind of world the treasure is hidden in, and plays the forces arrayed specifically to take away the happy-go-lucky freedom of the treasure-seekers (hereafter The Law). These can be anything, throughout all of history, mythology and fiction.
The players always play 18th century, carribean pirates.
How'd they get to the colony satellites around Procyon? They followed a treasure map. Duh!
The game is a team effort in which first one, then the next of the pirates leads the team on a Plan to find the treasure. All but the last plan will inevitably fail, but each time a plan fails the treasure is (behind the scenes of course) increased by a number of doubloons determined by how gutsy, risky and brilliant the plan was (as well as how well it used all of the unique skills of the team).
As the number of doubloons in the treasure increases, the adversity is empowered to become more and more ridiculously over the top. Yay!
There is no mechanic for success or failure. Pirates who are on their game never fail. There is, however, a mechanic to see how much circumstances shake the resolve (Steel) of the pirate. While their Steel is above zero, the pirate's actions succeed. When their Steel drops to zero the only action they can succeed at is breaking and running. Steel refreshes with the start of a new plan.