Straight out of college, Tiffany "Rex" Simpson barely misses a shot but isn't quite good enough to earn a spot on NASA's elite astronaut corps. A doctored application and some quick improvisation lands Rex in NASA's ultra-competitive astronaut training program. Over her head and out of her element, Rex must rely on her quick wit, moxie, and determination to get through training and into the cosmos before her cover is blown and she is kicked out of the program sooner than she wishes.