A brilliant, eccentric teenager must solve a series of puzzles left behind by her dead father in this debut that features codes, riddles, and a plot that ingeniously mixes fact and fiction.

When seventeen-year-old Arizona’s mother goes missing on a family trip, Arizona tells herself not to worry. Until she finds her family’s Airstream ransacked—and the ominous note on the counter. Incredibly, impossibly, her mother has been kidnapped.

Even more bizarre are the terms of the ransom: The kidnappers believe that Arizona’s dead father took some sort of great secret to his grave—and to get her mother back safely, Arizona must now uncover it for them.

If Arizona were a “normal” teenager, she’d have no idea what to do. Luckily, Arizona’s anything but normal. Like her father, she’s more comfortable with books than with people, and inordinately fond of puzzles, codes, and riddles—and she soon realizes that the trail begins with a cipher that points her West, to the peaks of the Sierra Nevada mountains.

With her dog Mojo at her side, Arizona sets off in the Airstream to uncover the truth and pursue her mother’s return on her own terms. Yet her journey grows far stranger than she could have imagined, as she finds herself cracking codes and solving riddles, poring through pages of ancient texts, poking through forgotten corners of U.S. history, and uncovering mysteries hidden in plain sight in the Western landscape—all on the hunt for an impossible, centuries-old prize.

Even as she races to stay a step ahead of her adversaries and wonders at her father’s hidden life, she begins to realize that navigating the outside world on her own isn’t as terrifying as she thought—and finding other people who understand her isn’t so impossible after all.