Fox's The New Mutants celebrates winter solstice with a brief but ominous new movie promo that warns, "Things will only get darker."

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While the text is an obvious allusion to the decreasing hours of daylight in winter, it doubles as a nod to the horror tone of director Josh Boone's upcoming X-Men spinoff.

Things will only get darker. #WinterSolstice pic.twitter.com/YQfsSkTNWj— New Mutants (@NewMutantsFilm) December 21, 2017

The clip, of Blu Hunt's Danielle Moonstar lying in the snow, evokes the final page of Marvel Comics' The New Mutants #18, by Chris Claremont and Bill Sienkiewicz, in which the students of Charles Xavier's School for Gifted Youngsters find their classmate after she's been cut down by the Demon Bear. The seminal "Demon Bear Saga" storyline is one of the film's major influences.

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Characterized as “a full-fledged horror movie set within the X-Men universe," The New Mutants transplants the super-powered teens from Xavier's school to a secret facility, where they're held against their will. While coming to terms with their own abilities, the five young mutants must also confront the sins of their pasts.

Arriving April 13, 2018, The New Mutants stars Maisie Williams (Game of Thrones) as Wolfsbane, Anya Taylor-Joy (Atlantis) as Magik, Charlie Heaton (Stranger Things) as Cannonball, Blu Hunt (The Originals) as Dani Moonstar and Henry Zaga (13 Reasons Why) as Sunspot.

From Marvel's New Mutants #18