Director Kelly Reichardt (Old Joy, Wendy and Lucy, Meek's Cutoff) has always been a master of atmosphere more than plotting. Her films are always wonderfully spare, moody affairs about inter-personal relationships. So it's no surprise that her newest, and downright plottiest film, about three eco-terrorists (Jesse Eisenberg, Dakota Fanning and Peter Sarsgaard) who plot to blow up a dam, succeeds mightily when it comes to creating tension but struggles a little more with making its plot run together smoothly.

Night Moves is an exciting development in Reichardt's career: the film's logline is the most arresting, high-concept pitch she's ever taken on. And for the first half of the film, it is wonderful to watch her take on a pulpier subject with her inimitable style. We watch Josh (Eisenberg), Dena (Fanning), and Harmon (Sarsgaard) come together to execute a plot we have a very thin grasp of for most of the film. Information, both logistical and personal, comes out in dribs and drabs. Josh and Harmon are older friends, and Dena is a newer element partially included for her money; their motivations are political, but we only hear snatches of reasoning as to why they're doing what they're doing.

Reichardt is smart enough to know we can connect the dots on the larger issues and is much more interested in the push and pull between the three leads, a situation in which no one really has the upper hand. Josh might have a crush on Dena, but he's at least trying not to let on. Harmon might be mad about more things than just hydro-electric dams, but this is where he's chosen to channel his brooding energy (Sarsgaard is certainly right for the role). Dena seems the most spirited in her convictions, but it belies a naiveté that the others lack.

Much of the film revolves around execution more than anything else, and that's when it works the best. Scenes of Dena trying to buy huge amounts of fertilizer without arousing suspicion, or Josh calmly driving through a police checkpoint, are unbearably anxious and brilliantly done. The audience's perspective is so low to the ground and limited to our three protagonists that any development, positive or negative, flows nicely. We're sure things could go wrong at any moment, but every success seems well-earned. The obscurity helps with the morality question too: everyone's motivations aren't talked out enough for us to really take a side. What they're doing seems terrible and dangerous, but we're so concerned with how it's happening that we don't just detach out of horror.

Then, the group spins apart, we stick with Eisenberg's character, and the movie gets a lot plottier, and not in a good way. Suddenly we're being told about how characters feel, and the morality of the bomb plot is being openly discussed in what feels like lectures masquerading as overhead dialogue. Reichardt maintains control over the film's taut mood, but every plot development feels depressingly familiar.

Eisenberg is doing incredibly guarded work, tapping into his nervous, mumbly energy that can so often be deployed for laughs but here works very well for darker, more inscrutable purposes. Fanning is doing her best work in years—Dena's strident attitude has the right air of over-compensation, although her spiral into doubt later in the film is frustratingly kept off-screen for too long.

The essential problem is that Night Moves builds to a big climax that it doesn't really earn, but you really want it to. The atmosphere is so perfectly realized, and the details all feel so right. But while Night Moves begins to spiral into personal drama, the remoteness of its characters becomes a hindrance and their increasingly desperate behavior feels like a necessary chore. Reichardt does enough with the genre trappings of the thriller, especially in the first act, to make Night Moves a worthwhile trip. It's just too bad she couldn't re-invent the hacky final act too.