Stephen King's IT just hit theaters, and already the Andres (Andy) Muschietti film is on track to become one of the most critically and commercially successful Stephen King adaptations ever. A sequel is basically guaranteed at this point. And fortunately, a sequel was always part of the plan. As New Line charges forward with IT: Chapter Two, we've put together a handy guide breaking down everything we know about the sequel so far, including which cast and crew are definitely back, how the story ties into the original, and more.