Although it's been long speculated that Overlord is a "secret" fourth Cloverfield film, set during World War II, the teaser trailer for the Bad Robot production finally does away with that notion. Instead, it's a period horror film that seemingly has nothing to do with giant alien monsters, but everything to do with gruesome Nazi experiments.

Directed by Julius Avery from a script by Billy Ray and Mark L. Smith, Overlord follows a small group of U.S. paratroopers shot down behind enemy lines in France, where they discover a secret German compound, home to horrific experiments intended to create a "thousand-year army."

While the test subjects aren't exactly zombies, and the film almost certainly doesn't refer to them as such, they're not entirely human, either. At least not any longer. "They have been given a purpose," the Nazi scientist says in sinister voiceover.

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That's pretty much all that's known about Overlord, which isn't surprising, given it's produced by J.J. Abrams, a proponent of the "mystery box" approach. The filmmaker addressed speculation in April about a potential connection to Cloverfield, saying this latest project is a “crazy sci-fi action horror film” but it's not part of the established franchise. However, plans for a fourth Cloverfield film are in the works.

Arriving Nov. 9 from Paramount Pictures, Overlord stars Jovan Adepo, John Magno, Wyatt Russell, Bokeem Woodbine, Pilou Asbaek, Jacob Anderson and Iain De Caestecker.