It appears from the video that Castle Rock is a series based on the fictional Maine town of Castle Rock.
According to THR, this will be a Hulu original anthology series that will “weave together characters and themes” from all King’s works that are located in or mention Castle Rock.
Each season will follow a group of characters and storylines but will bring in characters and themes from earlier seasons.
Does this mean we’re getting a series set in a shared King universe?