Thirteen-year-old Mia Winchell appears to be the most normal kid in her family. Her younger brother Zack keeps a chart of all the McDonald's hamburgers he's eaten in his lifetime. Her older sister Beth dyes her hair a different color every week and might be a witch. But Mia knows she is far from ordinary. She is keeping something from everyone who knows her: the fact that sounds, numbers, and letters have color for her.

When trouble in school finally convinces Mia to reveal her secret, she feels like a freak. Her family and friends have trouble relating to her as she embarks on an intense journey of self-discovery. By the time she realizes she has isolated herself from all the people who care about her, it is almost too late. She has to lose something very special in order to find herself.