Jim Mickle’s “Cold in July” is a peculiar mix of genres — at times, a revenge thriller, and at others, a noir slasher, with a splash of grindhouse. It can get messy at times, and there are some awkward changes in tone, but it never fails to be entertaining and unpredictable.

The movie revolves around Richard Dane (Michael C. Hall), a mild-mannered, upstanding East Texas citizen with a wife and son who runs a picture-framing store.

The trouble begins when he shoots an intruder dead in his home in the middle of the night. Being the passive, nonviolent fellow he is, this event leaves him nervous and shaking, even feeling guilty. Because of this guilt, he decides to attend the man’s funeral and runs into the intruder’s father, Russell (Sam Shepard), who’s just been granted parole and isn’t happy.

In many respects, Richard resembles a typical film-noir protagonist: the seemingly innocent civilian who puts his life and his family’s on the line. For a while, we think it’s going to be about Russell’s attempt to kill Richard out of vengeance and Richard’s obligation to protect his family from danger once again. And this is the way it plays out for a while: Russell stalks the family, seeming to materialize out of nowhere, similar to a horror-movie villain. And Jeff Grace’s old-school synthesizer soundtrack gives this entire section a slasher-film vibe.

However, this story resolves itself after about 20 minutes or so, when the movie mutates into something totally different. Richard becomes uncertain as to whether the guy he shot was actually Russell’s son and becomes suspicious that there’s a cover-up involving the police. Things take an even stranger turn when Russell and Richard join forces and together, with a Houston private eye (Don Johnson, decked out in cowboy gear) try to uncover what’s really going on.

In some respects, “Cold in July” plays out like a pulpier version of a Hitchcock film. Screenwriters Mickle and Nick Damici (based on the book by Joe R. Lansdale) keep the viewers on their toes the entire time. Near the end. when the final disturbing twist of the plot is revealed (accompanied by Grace’s synthesizer music again), it turns into a full-blown, gory, ‘70s/8’0s grindhouse-style movie.

Admittedly, “Cold in July” doesn’t have quite the same finesse of a Hitchcock film, with the sudden shifts in tone. The movie primarily wants to be dark, but at times, it veers into silliness, which doesn’t always work.

Nevertheless, the picture still succeeds in being a tense and compelling Southern noir. Hall, who’s known mainly for playing a serial killer with a strict moral code on the TV show “Dexter,” does a fantastic job of portraying an innocent family man who becomes capable of doing violent acts for the sake of good. Shepard goes from being an intimidating ex-con in search of vengeance to a concerned father in search of truth and ultimately needs to make an extremely tough decision. And Johnson is amusing as the private eye, who provides a little comic relief as the film mines darker and darker territory.

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