From the publisher's blurb
A system that’s easy to learn and simple to use.
The subtlety and nuance lies in how you choose to interpret the die rolls and use them to tell your story. Here’s a quick overview of how the system works.
There When You Need It
Most of the time, you can use the context of the story and established abilities of the characters to decide what happens without having to roll any dice. Do what makes sense, seems logical, and makes for an interesting story. There are only two times when you need to roll dice:
The outcome is uncertain. The action that a character wants to undertake could succeed or fail, so you roll dice to find out which. Or, there are risks inherent in undertaking the action, so you roll to see if the character succeeds and overcomes those risks, or fails and has to deal with the complications.
You need to determine the degree of success or failure. You know that the character will probably succeed, but how well they manage to do so will matter. Or, even though you know the character will probably fail, the degree to which they fail holds some significance. The rewards and complications can impact the story going forward, so die rolls are required to help better define the outcomes.
Bid on Risks and Rewards
When you decide what action you’d like your character to take, you bid a die type (d4, d6, d8, d10, or d12). This represents both the risk you’re willing to take and the reward you’d like to achieve. The bigger the die, the greater the degree of success or failure. The more the character stands to gain if you succeed, the greater the injury or other complications the character will suffer if you fail.
Roll a d20 and Add Modifiers
The player declares what they’d like the character to do, and then rolls a 20-sided die. Add any bonuses the character is able to use, as well as any situational modifiers that the guide might impose, to the rolled result. There are no target numbers to compare the total to; all you need to keep track of is whether the total of the roll and modifiers is high or low, even or odd.
High or Low, Success or Failure
If the total of your roll plus modifiers is high (11 or more) your character succeeds. If your total is low (10 or less) you character fails. That’s it. No charts, no tables, and no screen are required to figure out whether your character succeeded or failed. You can focus on the story, not the dice.
Even or Odd, Narrating the Outcome
If your total of roll plus modifiers is an even number, you get to describe what happens. If your total is an odd number, the guide describes what happens. You can make your successes sound far more impressive, and your failures less painful. The guide can make your victories look like luck, and your failures look embarrassing.
Nobody Dies Accidentally
Because Lighthouse leans toward being a storytelling activity and away from being a game, it’s impossible for characters to simply die randomly because of bad die rolls or even poor choices. A character’s death has to make sense in the context of the story. It should also have emotional impact, as it does in fiction. Finally, the player and the guide have to agree that the character’s death is appropriate and adds something interesting or important to the story.