Indeed, the derivative nature of "Sabrina" — and the reason it doesn't feel quite like a premium offering — is underscored by the fact that the CW offers its own very similar approach to teens immersed in the supernatural, "Legacies," the same week. That one — about, yes, a boarding school for teens with supernatural gifts (or curses) — comes courtesy of producer Julie Plec, and has a foot (or two) rooted in her prior creations "The Vampire Diaries" and "The Originals."Like "Riverdale," "Sabrina" hails from series creator Roberto Aguirre-Sacasa and producer Greg Berlanti, whose TV empire includes the CW's lineup of superhero shows. He and his collaborators have a knack for tweaking existing properties, bringing them into the 21st century with catering to a younger audience.What most sets "Sabrina" apart, however, given its familiar cauldron, is the casting, with "Mad Men's" now-grownup Kiernan Shipka in the title role, being raised by her two eccentric aunts (Mirando Otto, "Wonder Woman's" Lucy Davis), while coming to grips with her rather significant legacy, as outlined to her by Father Blackwood (Richard Coyle), High Priest of the Church of the Night.Sabrina was also orphaned, and her father was a renowned witch who married a mortal. A chip off the old block, Sabrina's life — and sorcerous inheritance — is complicated by her relationship with a mortal boy, played by Disney Channel heartthrob Ross Lynch.There's a superhero aspect to the early episodes, as Sabrina tries to juggle her unsuspecting friends with an opportunity to attend the Academy of Unseen Arts and, having come of age, sign herself over to the Dark Lord. Along the way, though, the writers conjure a number of what might be called episodic threats — such as exorcising a wayward demon — even as Sabrina grapples with how to find her place between the two worlds pulling at her.Of course, if you're going to put something together this derivative, the producers at least have the smarts to borrow from the best. The episodes clip along at a reasonably brisk pace, with Sabrina exhibiting flashes of her powers while resisting some of the more arcane aspects of what might be called witch culture.While the gothic backdrop and juicy performances give "Sabrina" zest, the show feels lacking in the qualities that would distinguish it from "Charmed," or "Legacies," whose ensemble cast includes not just teenage witches but vampires, werewolves and hybrids.At the center of it all is Hope (Danielle Rose Russell), the 17-year-old daughter of "The Originals'" Klaus Mikaelson, living in what feels like a cross between Hogwarts and Professor Xavier's School for Gifted Mutants. Inevitably, there are new arrivals, which helpfully provides the existing characters a chance to explain everything during the pilot.It's slickly produced, but it all comes back to a formula that CW has mined a few times too many, where raging teen hormones are further complicated by extraordinary abilities. Granted, vampires are undead, but it might be time for them to at least take a bit of a rest.Then again, CW knows its audience, and Netflix caters to various demographics, including the one that will be curious about these "Chilling Adventures." It's just that with so many similarly pitched series flying around, these latest takes on teenage witches don't quite separate themselves from the pack enough to be worth hunting."The Chilling Adventures of Sabrina" premieres Oct. 26 on Netflix. "Legacies" premieres Oct. 25 at 9 p.m. EST on the CW.