Anna Mae Shetler is a tomboy who loves nothing more than exploring the woods with her two best friends, Amos and Jeremiah. During a game of hide and seek they stumble upon a mystery that will threaten to tear apart their friendship, and--as they soon discover--it's a mystery that caused a rift in their families decades earlier.

Anna Mae and her friends are playing in the old tree house in the woods when a floor board suddenly breaks. No one is seriously hurt, but when they take a second look, they see that a metal box of money and a diary are hidden under the floor in the...