From publisher blurb:
A short magic system for Fate Core.
The rules for challenges in Fate Core make a perfect structure for performing ritual magic. Different actions can represent the hours of preparation, cleansing a ritual space, gathering materials, and so on. Rituals and Convergences presents ideas for running ritual magic challeneges, including new stunts tailored to the structure.
Rituals and Convergences also introduces the idea of the magical Convergence, a specific time imbued with magical potential (in the form of aspects and stunts) that the ritualists can use to their advantage. The magical traits you generate during the ritual challenge allow you to perform unique and powerful effects. Example aspects and stunts provide a good idea of what Convergences can do for your game.