Ever since Part 1 premiered, Chilling Adventures of Sabrina has kept coy about how exactly the series is related to Riverdale. Both Archie Comics-inspired shows make frequent nods to one another, but they have yet to pull the trigger on a full crossover. However, Sabrina may have finally explained how the two worlds are connected in its final season, and the theory that Sabrina and Riverdale are set in parallel dimensions has never been stronger.
Spoiler alert: This post contains spoilers from Chilling Adventures of Sabrina Part 4. Sabrina has included a bunch of winks to Riverdale throughout its four installments, from calling out iconic landmarks like Sweetwater River and Pop's Diner to featuring Riverdale actors in cameo roles. Sabrina even took a quick trip to Riverdale in Part 3, although she stayed in the woods and never actually ventured into town. Part 4 included even more nods to CAOS' sister series, and a few cameos plus a surprising plot point seem to lend a lot of credence to the theory that Sabrina's Greendale actually exists in a parallel dimension to the Riverdale that Archie, Betty, Jughead, and Veronica reside in.
In one episode of Sabrina's final season, Harvey's band the Fright Club is preparing to take on a familiar-looking band called the Stoned Philosophers in a battle of the bands. The group is led by none other than Bret Weston Wallis and Donna Sweett... or, at least it seemed that way. Actors Sean Depner and Sarah Desjardins are actually not reprising their Stonewall Prep characters in Sabrina, as Harvey revealed when he referred to Depner's character as Tobey instead of Bret.
The cameo is the latest of many Riverdale actors appearing in CAOS in different roles. Jughead's rival Kurtz is now Theo's hobgoblin boyfriend Robin, the Gargoyle King's victim Ben Button delivered a pizza to Lilith after his Riverdale death, and Penelope Blossom appeared as a glamour used by Prudence.
Given all the dual roles, it would make sense that Sabrina is set in a parallel dimension to Riverdale, where the Riverdale residents lead slightly different lives to the ones depicted on Riverdale.
The final episodes of CAOS drive home the concept of parallel dimensions, as Sabrina sends her altered-timeline clone to a mirror realm that is hurdling toward her realm. Sabrina's Hell-dwelling clone Sabrina Morningstar finds herself trapped in a dimension modeled after the original Sabrina the Teenage Witch sitcom, and the episode works as a long-awaited crossover featuring the original Hilda and Zelda (Caroline Rhea and Beth Broderick) and even a talking Salem.
Since Sabrina had to jump dimensions for that crossover, it is also likely true that Riverdale is in another parallel dimension as well. Sadly, fans likely won't get to see that concept explored. Showrunner Roberto Aguirre-Sacasa revealed CAOS Part 5 was planned to include a big Riverdale crossover, but Netflix canceled the show after Part 4, so fans will just have to hope the ongoing Riverdale may choose to incorporate some Sabrina easter eggs in the future.