From the publisher's blurb:
Invisible Sun is a game of secrets. And that is true of both the physical product and the in-world game as it is played. Hidden within the pages of the books, within the components of the game, and perhaps even within the box itself, lie clues to discover—clues that can unlock new secrets. Invisible Sun is as much about interacting with the physical game itself as it is about interacting with the other players. This is a game of deep immersion. Of escape.
Players create in-depth and intricate characters where the house in which they live is as important as their stats and skills. Character choices drive everything, with game rewards based on personalized story arcs, and emergent mechanics arising from not just from character creation, but from ongoing character development. However, in the end, it’s not game mechanics that dominate gameplay, but roleplaying.
Player characters in Invisible Sun discover and utilize secrets. These secrets often involve the very nature of the universe, and those who master such secrets can change that nature. In common parlance, this is magic, and thus player characters are magicians and sorcerers called vislae. How they utilize their magic—casting spells, creating objects of great power, entreating with otherworldly spirits, or improvising effects by weaving together threads of power—is up to them. Character creation and customization are paramount, and no character concept is refused. In a game where everything is possible, it’s never a matter of “You can’t do that,” but “How do you go about discovering the secret to do that?”