This is Opus. The fantasy roleplaying game and storytelling guide we use for the show. It's unique in being able to generate whole sessions for you at improvisational speed, allowing you to run full, rich sessions without any planning at all. It's still in development but the final product will be available this year. You can access it for free right now while it's being made.
Below are the final materials for Opus. The full Bestiary, 20 Missions to run your party through, detailed entries on every spell and ability in the game, and some additional fun minor rules. Again you can access all of this for free while it's in development. Should be done soon!