From the publisher's website:
Moirai is a simple, generic role-playing game system for story heavy games. The system is based upon use of a “Fate Ball,”* but can be played with a single D20 if need be. Where will your Moirai stories take place? How will your Moirai adventures unfold?
The PDF includes:
-Printer Friendly Quick Sheet of Rules
(*- Note: We fear lawyers, so we are avoiding all direct references to its true name. The “Fate Ball” is that toy divination orb that looks like a pool ball and is used by asking it yes or no questions. The replies to your questions appear in its bottom window.)