Penny has never met anyone smarter than her. That's par for the course when you're a savant—one of less than one hundred in the world. But despite her photographic memory and super-powered intellect, there's one question Penny doesn't know the answer to: where did her father go when he left her and her mother years ago? On Penny's 21st birthday, she receives a card in the mail from her father, just as she has every year since he left. But this birthday card is different. For the first time ever, there's a return address. Penny may not know much about the world beyond The Institute, the special school she has attended since her abilities became clear, but now seems like the perfect time to break free of her safe existence and start to really live. What she doesn't realize is that the real world is more complicated and dangerous than she ever imagined...