Downton Abbey‘s Dan Stevens is a seemingly well-intentioned Iraq vet who visits the grieving family of his fallen war buddy in action-horror-thriller The Guest, directed by Adam Wingard. The hotly anticipated genre-blender is scripted by Wingard’s You’re Next collaborator Simon Barrett and also stars Maika Monroe, Leland Orser, Sheila Kelley, Brendan Meyer and Lance Reddick. Check out the full U.S. trailer just released by Picturehouse, which nabbed The Guest after its Sundance debut and opens the flick September 17: