A new trailer for The Guest has arrived online this week, revealing a bit more of the plot without giving too much away. This is the latest film from Adam Wingard and Simon Barrett (You’re Next) and it stars Dan Stevens (Downton Abbey) as an Iraq war vet who mysteriously shows up at the home of a fallen comrade, telling them that their son wanted him to keep an eye on his family. At first, he seems to be helping them out in various ways, but he is also clearly hiding something. The movie looks a lot more action-oriented than expected and also contains some of Wingard and Barrett’s trademark dark humour as well. The Guest hits theatres on Sept. 17th; check out the trailer after the jump and let us know what you think.