Former engineer Shane Carruth makes an impressive debut with this low-budget, low-tech suspense film about two ambitious inventors (played by himself and David Sullivan) who stumble onto the secret of time travel. With no whiz-bang effects at its disposal, the movie sticks to the fever of inquiry and the practical complications that ensue as the young men try to figure out what they’ve got and how to exploit it. Carruth has cited 70s paranoid thrillers like The Conversation and All the President’s Men as his models, and their influence is evident in the movie’s hushed tone and oppressively overlit institutional spaces. A half-baked conspiracy subplot in the last third makes Carruth’s knotty narrative even harder to follow, but this is still scary, puzzling, and different. PG-13, 80 min. Landmark’s Century Centre.