In this film, a nurse on her first day has to work the overnight shift in a hospital that to conserve power during a crisis, shuts the power off throughout the night. But of-course when the lights are out, things get more interesting. Atmosphere is key here and the film does an incredible job of establishing one that's dark and increasingly more eerie as the film progresses. Some scenes take full advantage of that dynamic to generate some really creepy moments. It's a slow burn that concludes with a satisfying ending that delivers a message. Also, not to be forgotten is the performance by Rose Victoria Williams , she's does a great job.