Part sci-fi and part psychological horror, No One Will Save You is an impressive outing that serves as a vehicle for Dever’s one-woman show. She is a powerhouse, a nonstop show of talent that doesn’t seem to run out of fuel. The scenes are grueling and excruciating, they involve a lot of physical, mental, and emotional turmoil, but somehow, Dever rises to the challenge with unbelievable ease. Sure, sci-fi lovers will find much to discuss in these unearthly creatures, and cinephiles will appreciate how the film relies almost solely on sound design and a single line of dialogue. But it’s Dever who does the heavy lifting here, and it’s especially apparent when the film tries, weakly, to delve into Brynn’s psyche and the town’s sociological workings. It’s not as impressive in those regards, but Dever is strong enough an actress to make you forgive the movie’s frailer parts.