’The Desperate Hour,’ a film lost in the woods

To say Naomi Watts is the only star in "The Desperate Hour" is a little misleading. She's pretty much the only person in the film, that's true. But you could make the case that she has a co-star in her iPhone.

Watts spends most of "The Desperate Hour" furiously typing, listening, consulting, pleading or otherwise glued to her smartphone as it takes on an outsized importance. Alone and lost in the woods, it's her only lifeline to the world.

Watts plays Amy Carr as the first anniversary of her husband's death approaches. She has a young daughter and a sullen, depressed teenage son. She goes on a five-mile jog into a forest and then finds out there's been a shooting at the local school. The film's meat is her harrowing hour of not knowing what's happening in gut-twisting worry.

As an acting exercise, it's intriguing, barely any scene partners and all unfolding in real time. As a film, not so much: After a plodding, placid start, it goes from first gear into fifth and never relents as the woes pile on.

It turns out watching an hour of Watts breathing heavily as she runs and gets more frantic, her eyes ever widening, isn't that much fun. At one point, Watts' character rolls her ankle, forcing her to limp the rest of the way. You might roll your eyes. Method limping.

Director Phillip Noyce squeezes out every possible trick to keep us interested. There are high, overhead shots of Watts running through colorful trees and shots of her looking upward from the dirt path. The camera sometimes swirls around her face like a wasp and ominous music swells.

In some ways, "The Desperate Hour" could be seen like an 84-minute commercial for the iPhone, as our heroine flips from FaceTime to live TV, one-touch Contacts, listens to music through...