From the publisher's page: The stars are right for Great Cthulhu’s return. It’s up to you to make them wrong again! The Great Old Ones reach out from the future and into their past—our present—corrupting the timeline such that events and individuals turn towards the apocalyptic and lead to their inevitable rise. A small and battered resistance effort mounted by time-travelers and present-day heroes stands in their way. You are those one-way travelers from a dark future and their crucial allies from the present day, working together to save the human race from looming apocalypse. Armed with foreknowledge of Judgment Day, you must succeed at a series of vital missions aimed at restoring hope to the future. Can you defeat the vast unknowable evils of the Great Old Ones before you become a monster yourself? Find out in Fate of Cthulhu! Fate of Cthulhu is a stand-alone game powered by the Fate Core System. No other books are needed to play. In this game, you’ll find: Corruption mechanics that show how close your heroes are coming to the monsters they fight, and the monstrous abilities they gain! Five detailed example timelines plus rules for running them and making your own. A system for tracking key events leading up to the apocalypse that the players change through their actions and choices during play, including support for ripple effects and time paradoxes. Modifications to stress and concession rules, including support for heroic last stands that sacrifice a character but help turn the timeline towards a better outcome. A rituals and spells system that offers great power at a cost, treating spells as secrets of arcane Elder technology that must be sought out in play.