Is this a sequel to Bad Robot’s 2008 found footage Monster movie Cloverfield? Sorry everyone, but since this is a Bad Robot joint, we have no real idea. But it is a film that exists, and you can make your guesses as to what it’s about now, as the official trailer, which premiered tonight in front of screenings of Michael Bay’s 13 Hours, has now been released online. Watch it here.

I’ll admit I’m impressed. Somehow, Bad Robot managed to sneak 10 Cloverfield Lane through production without anyone becoming wise to the fact that A) it was the untitled Bad Robot film first talked about back in 2014 and B) it was actually in the can. For once, the mystery box manages to impress instead of annoy.

An official plot synopsis has not been released, but what we know is that it’s an apocalyptic thriller starring John Goodman, Mary Elizabeth Winstead, and John Gallagher Jr., set in what appears to be a well insulated and fully powered underground shelter of some kind, with unseen and unknown dangers waiting just outside the door. At least, however, we know that title isn’t an accident. In a statement to Collider shortly after the trailer dropped, Paramount elaborated just a bit more, saying that 10 Cloverfield Lane is intended to be a “blood relative” to the earlier film which shares a word in common in the title. Whether that means a direct sequel, an anthology series, or a thematic trilogy, we’ll have to wait to find out.

It’s written by Josh Campbell & Matthew Stuecken and Damien Chazelle, and directed by Dan Trachtenberg, and hits theaters March 11.