The Maze of Bones (The 39 Clues, #1)
by Rick Riordan
Grace Cahill decides to change her will on her death bed. As the matriarch of a widespread and illustrious clan, she offers certain relatives the chance of walking away with $1M or a clue that could lead them to power.
Amy and Dan, who always thought they were Grace’s favorites, decide to take the clue. This puts them into the race with some very unscrupulous relatives and at odds with their guardian, Grace’s sister.
They flee the will reading on a race to find a clue that is related to Ben Franklin (who happens to be a relative). They are told by the executor, Mr. McIntyre, to trust no one, but they have to bring along their au pair, Nellie, because they need an adult.
Will they find the clues and, maybe even, how their parents died?