Agnes (Ashley Judd) is a desperate woman with an abusive creep for an ex-husband (Harry Connick Jr.) and enough personal demons for two lifetimes. Drowning her considerable sorrows in drink and drugs, she's introduced to Peter (Michael Shannon) and the two hit it off. Peter is a strange, withdrawn man, but Agnes finds compassion from the stranger and the two bond immediately. During their first night together, Peter discovers microscopic bugs in the seedy hotel room, opening his reservoir of lethal fixation as he traces the invisible insects into his bloodstream, slowly convincing Agnes into believing that their bodies are infested with these tiny agents of the government.

Adapted by Tracy Letts from his own 1996 stage play, "Bug" is an effective piece of unease, using the compact space of a filthy hotel room to incubate delirium and nightmarish displays of loyalty and insanity. What pops the polluted bubble of the film version is the thought that perhaps this war on reason was at its best on the stage, where the rougher, flamboyant edges of the narrative had a more horrific effect.

Legendary director William Friedkin ("The Exorcist") seems an apt choice for this material. Well versed in dramatizing unfathomable despair and damage, Friedkin lends "Bug" a sensible amount of air. The film is not a looping ride of scares, but a slow build, using a good 60 minutes of running time to understand the characters and their insecurities before he lets the premise drop off into hell as scripted. "Bug" is a low-budget picture and it shows at times, but it has a tenacity to it, or at least a defiance, to follow its own pace. Friedkin shows more patience here than most directors would.

The question I have is if this play needed the cinematic treatment at all. While gripping in faint ways, "Bug" loses its balance at several points during the story because the camera is in too close to the action, pinpointing the mania of the concept rather than allowing it to sneak up behind the audience. The stage also allows for the actors to expand on their bug-infested performance tics without the unforgiving eye of the camera revealing a limitation of talent. God bless Judd and Shannon, who play at the tempo needed, but once the infestation reaches a frenzied point, their displays of irritation are best left for a more forgiving distance.

"Bug" isn't interested in a fever pitch; another reason for horror fans to readjust their antennae before walking into the theater. The film has moments of nastiness and bloodletting, but it's more concerned with actorly monologues and psychological snowballing in the final moments, while also pulling governmental conspiracies tied to various homeland terrorists and cult leaders out of its behind at the last minute. It's an exhausting experience that overstays its welcome, but "Bug" is unique in its priorities; a quality Lionsgate should've been eager to celebrate rather than keep away from online press and accurate promotion.