Anna (Beth Riesgraf) is an agoraphobic young woman who hasn’t left the family house in a decade. Her brother Conrad (Timothy T. McKinney) is her only companion, but he’s dying in the film’s opening scenes. A nice Meals on Wheels guy (Rory Culkin) is one of Anna’s few connections to the outside world. These opening scenes define Anna’s world well, and Riesgraf is very good in them, conveying someone who’s actually more scared of going out her front door than anything that might come through it. After her brother’s passing, Riesgraf deftly conveys Anna’s crippling fear, agoraphobia so bad that it keeps her from even going to the funeral.

And that’s when the problems start. Three guys (Jack Kesy, Joshua Mikel and Martin Starr) who presumed that Anna would be out of the house break into it to rob the place. Anna is still home, dressed up for the funeral but unable to will herself to go. At first, it looks like “Intruders” may play out like “Panic Room,” as the home invaders realize that someone has altered their plans. However, it’s not long before the tables are turned, leaving the men in a basement that’s, well, not your average lower floor. It turns out that Anna has a dark family history and the men who thought they could steal her family fortune are about to confront it.

While the three criminals who bust through Anna’s front door are relatively and predictably defined—one killer, one peaceful guy, one leader—the cast and setting sell the action. We believe Anna is so crippled by fear that her captors don’t even think they have to tie her up to stop her from escaping. The filmmaking in this first act is lean and tight, ably propelled by Riesgraf and the always-great Starr, playing against type here as the maniac who wants to plunge a hammer into Anna’s head. I could do without the shaky camerawork to capture Anna’s fear (the actress is good enough that the trick is unnecessary), but I was down with “Intruders” until a major incident at the 30-minute mark completely changes the stakes and dynamic.

ncG1vNJzZmivp6x7s7vGnqmempWnwW%2BvzqZmq52mnrK4v46ipa2qpZmys7%2BMa2dqbg%3D%3D