Twelve-year-old Ivy Aberdeen's house is destroyed in a tornado, and in the aftermath of the storm, she begins to develop feelings for another girl at school.

Harassed at her middle school, not taken seriously at home, and with a "perfect" older brother, Matthew, to live up to, thirteen-year-old Claire has always felt like her life was cursed--then one morning, when she are her beloved father are talking at breakfast, her father suddenly falls over with a stroke, and suddenly everything changes.

Lost in the Black Forest, Otto meets three mysterious sisters and finds himself entwined in a prophecy, a promise, and a harmonica...and decades later three children, Friedrich in Germany, Mike in Pennsylvania, and Ivy in California find themselves caught up in the same thread of destiny in the darkest days of the twentieth century, struggling to keep their families intact, and tied together by the music of the same harmonica