Isabel, an eleven-year-old from Havana, Cuba, is one of the protagonists of the book. Isabel is smart, determined, and inventive. Despite the dangers she faces over the course of the book, she continues to hope for things to improve. While others argue over how to react to new situations, Isabel strikes out to find solutions, for example, finding them a boat and gasoline to escape Cuba while the adults argue over whether to go. Isabel puts the needs of her family above her own desires, a quality exemplified by her decision to trade her trumpet for the gasoline. The trumpet is Isabel’s prized possession and a means of expressing herself. Giving it up for the gasoline shows the severity of the danger Papi faces and the strength of Isabel’s desire to help her family. However, as much as she loves her trumpet, she loves her family more. When Lito realizes she has traded the trumpet, he is shocked, calling it her “everything.” However, Isabel corrects him in her head, thinking that it wasn’t everything, since it wasn’t her parents or him. Her confidence that she can get another trumpet in the U.S. demonstrates her hopeful attitude towards the future. 

Isabel sees the world in musical terms, a natural extension of her identity as a musician. She thinks of a life as a symphony, made up of many separate movements and musical ideas. A song, she thinks, is an incident in a life. Even while in great danger, her thoughts turn to music. During the storm at sea, when she thinks of the song of their journey, assigning each part of the story a musical match, wondering what events will become the refrain and the coda that ends the song. Music is so important to Isabel that her difficulty counting and clapping the clave rhythm that runs through Cuban music provokes a crisis within her. Although she imagines while living in Cuba that the rhythm will eventually come to her in time, when she still can’t feel it on the boat, she worries that she will never learn it, now that she has left Cuba. The clave is more than a musical idea to Isabel: it represents an authentic Cuban identity she fears she has lost by leaving. However, when she plays the U.S. national anthem on the replacement trumpet Uncle Guillermo buys her in Miami, she finds the clave at last. Despite leaving Cuba, she has not left her Cuban identity behind.