Seven-year-old B Browning doesn't know why sometimes he feels like wearing overalls and a flannel shirt and other days wakes up wishing he could dress like his sister Patti-Anne. He knows it bothers and confuses people, even the people who love him, but it feels just right to B. But when B and Mia, the bossiest kid at New Horizons School, both decide to try out for the part of the Mermaid in the Spring play, B wonders how he'll ever survive the year.