The Maze of Bones (The 39 Clues, Book 1)

In the first book of the bestselling series, young siblings Amy and Dan Cahill face a life-altering decision when their matriarch, Grace Cahill, leaves them a will that offers either one million dollars or a chance to uncover a family secret. As they embark on a globe-spanning quest to find the 39 hidden clues that promise to reveal their family's powerful legacy, they must balance the thrill of the hunt with the mystery surrounding their parents' fate. The adventure intertwines historical figures and puzzles, challenging them to uncover the truth about their heritage.