IT'S THE FOURTH OF JULY. A beautiful hipster couple stands on the Brooklyn Bridge, trying to make a decision.

"Is today the day?" asks Joseph Gordon-Levitt. "I don't know," Lynn Collins replies. "Maybe." (This is what happens when you ask actors to improvise their dialogue.) Are they trying to decide if they'll spend the day in Brooklyn or Manhattan, or are the stakes much higher? A coin is flipped; the couple sprints for opposite ends of the bridge. In Brooklyn, a green sedan awaits; in Manhattan, a yellow cab. And Uncertainty splits into two parallel storylines, readily identified by their color schemes. In Brooklyn, the green-clad couple attends a family barbeque, where they agonize over whether to reveal Collins' character's pregnancy; in Manhattan, dressed in yellow, they find a cell phone in their cab, and returning it to its owner becomes a matter of life and death.

Filmmakers Scott McGehee and David Siegel are clearly experimenting with genre, so it would be unfair to call the Manhattan half of the movie "implausible." (It is fair, though, to say that the film asks the audience to take cell phones far too seriously.) The scenes set in Brooklyn are far better, but ultimately, the two halves of the story have nothing to say to each other—there's no reason why either story is being told this way, and no real reason why this beautiful, boring couple deserves our attention.