 In the comedy Space Cadet, now streaming on Prime Video, Emma Roberts plays Rex Simpson, a young woman who's always had big dreams. When Rex was younger, she was a scholarly dynamo, so she set her sights on becoming an astronaut. But when her mom died, Rex's life collapsed, and her hopes of traveling to space went with it. A series of unlikely events, though, gives Rex another shot at fulfilling her dreams. There's just one problem. That chance depends on a lot of lies.