Warning: FULL SPOILERS follow for Castle Rock Season 1, Episode 6, titled "Filter." Castle Rock was renewed for Season 2 earlier this week. The Stephen King Universe just got a whole lot bigger in Castle Rock Episode 6, with a reveal that hints to a possible Dark Tower connection. For those uninitiated in the Kingverse mythology, the Dark Tower (also the name of an 8-part book series) is the center of the Stephen King multiverse and serves as the metanarrative that ties together and separates the individual realities of the Stephen King universe.