The film stirs richer, truer feelings once it becomes a one-man show. This is due both to Heisserer's and Walker's skill — the tension is strong, the scenario elemental, and Walker's harried, urgent hero is compelling — but also the fact that the movies are really good at dudes doing things, especially when those things are scrappy, desperate, and heroic.

Mr. Walker is convincing as a man battling grief, exhaustion and, occasionally, an intruding outside world where lawlessness has taken hold.

Heisserer is able to keep the thrills coming while maintaining an emotional tether to the character and the situation. While occasionally the movie veers into the realm of implausible melodrama, it's a well-modulated affair and knows exactly when to pull itself back from the brink.

Though a screenwriter by profession, Heisserer proves to be more economical with style than storytelling. Like a few too many contemporary genre films, Hours suffers from flashbackitis, a chronic condition that leads filmmakers to believe that a tragic backstory will add gravitas.

Most of the movie elicits tense empathy, which builds to a genuinely nerve-wracking sense of dread.