Trials (9e)
A trial is a test of strength and prowess, whether physical, mental, social, or otherwise. It is a task that the party cannot solve through fighting, or at least not through fighting alone.
Plus and Minus
The main mechanic of a trial is the accumulation of plus and minus points. The party needs to accumulate plus points while avoiding minus points, aiming for a goal number. If they gain plus points equal to the goal number, they succeed at the trial. If they gain minus points equal to the goal number, they fail at the trial.
However, each opposing point can be traded for a benefit or a complication after the trial. For instance, the party is trying to convince a nobleman to allow them access to the quarantined district of a city, so they can find the source of the plague that is threatening to spread across the country. The DM decides that this is a fairly difficult trial, because the nobleman thinks it is a foolhardy risk, so the goal number is 6.
Through skill checks, trait use, and roleplaying, the party manages to accumulate six plus points, but also two minus points. So they are permitted to enter the quarantined district, but the DM has two complications that can be introduced. The DM decides to spend the first one right away, making the nobleman demand that they take a skilled plague doctor with them, and ensure his security and safe return.
The party agrees, and the DM keeps the second complication in reserve until they are deep within the quarantined district, revealing the plague doctor as an unstable quack who believes that he can single-handedly cure the plague with a snake oil concoction he brewed up, an unstable potion that will only make things worse. The party has more to deal with now, and cannot simply leave him locked up somewhere, as they promised his safe return already.
When a trial has been failed, the players can spend their plus points to mitigate the circumstances. If they had failed to convince the nobleman, yet had gotten two plus points, they could immediately spend one to find a less-than-legal way into the quarantined district.
Success and Failure
Failing a trial should never mean failing the trial completely. If the party's trial is to find a hidden jungle temple, for example, then failing to make that result should not leave them hopelessly stranding in the wilderness. If the game is a story, then there should never be a chapter where the characters gripe about map directions and walk in circles.
If the party fails to find the hidden jungle temple, think of where they could end up instead. Perhaps they fall victim to a natural hazard and wind up in an underground river which takes them to the jungle temple, but leaves them stuck there without an easy way out. Or they could stumble across the remains of a previous expedition, and become aware that there may be sinister forces out there hunting down anyone who dares approach the temple.
Things should escalate, but never stall. Encourage the use of plus points to bounce back quickly from a failed trial.