A road trip to find closure...or a reckless chase that could turn deadly? 

Penny has never met anyone smarter than her. That's par for the course when you're a savant --- one of less than 100 in the world. But despite her photographic memory and super-powered intellect, there's one mystery Penny's never been able to solve: why did her father leave when she was in a coma at age seven, and where is he now?

On Penny's 21st birthday, she receives a card in the mail from him, 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. And a goodbye.

Penny doesn't know the world beyond her mother's house and the special school she's attended since her unusual abilities revealed themselves, but the mystery of her father's disappearance becomes her new obsession. For the first time ever she decides to leave home, to break free of everything that has kept her safe, and use her gifts to answer the questions that have always eluded her. What Penny doesn't realize is she might not be able to outsmart a world far more complicated and dangerous than she'd ever imagined.