Truths Too Terrible is a game of deduction in a monster noir world full of strange and unknowable mysteries. The players are investigators within that world, each attempting to understand the facts of a series of strange occurrences. These facts are made up of 6 different types of evidence, each of which could turn out to be pertinent, irrelevant, or unknowable. Each round, a set of facts is put aside, and the players must then attempt to deduce those facts (or, if necessary, make their best guess). At the end of each round, the player who can identify the most facts without getting any wrong will learn a Terrible Truth about the world. The first to learn 3 Terrible Truths wins the game.