Giant interstellar shoot-outs and outlandish alien races are great and all, but science fiction is a genre that can benefit from limitations as much as it can big-budget space operatics. It's built on ideas, which means that with enough ingenuity, a smaller movie can do its own world-building by exploring a concept and how it affects people. Large-scope sci-fi may be big for the summer box office, but there's also a long tradition of scrappier films exploring time or space travel, dark futures, and new technology, all by way of how it affects a small group of characters, an approach that can be just as mind-bending without the visual effects. When you can't depend on simply showing how crazy a sci-fi phenomenon looks, for instance, you're forced to concentrate more on what the experience of dealing with it is like, and those tropes can serve as a metaphor for experiences that are closer to home for the audience.

That's the case for Coherence, an inventive indie written and directed by James Ward Byrkit that opens in New York and Los Angeles this Friday and expands to more cities in the weeks after. Coherence is the story of a dinner party in which eight friends with long and sometimes fraught histories gather to play catch-up while a comet passes overhead. When the power goes out, they notice there's a house two blocks away that remains lit, and a few of the guests venture out to see if they can use the phone. When they come back, one of them's bleeding and upset by what he saw, and the other is carrying a mysterious box he stole that turns out to be inexplicably filled with photos of everyone at the party.