Echo follows three children in different times and places whose lives are mysteriously connected by a magical harmonica. Friedrich in Nazi Germany, Mike in Depression-era Pennsylvania, and Ivy in World War II California each face their own struggles—persecution, family separation, and prejudice—while the harmonica brings them hope and courage. Their separate journeys eventually weave together in a surprising and beautiful finale that shows how music can transcend time and hardship. This novel celebrates the power of music, resilience, and how small acts of kindness can echo through history.