Charlie is in the third grade and lives in a small town in the Sawtooth Mountains in Idaho. Her real name is Charlotte, but she thinks that it's too proper for a girl who doesn't like to wear dresses or get her hair combed. Charlie likes to catch frogs and play with bugs. Her sisters and brother call her stubborn, but Charlie knows she is just determined. Every year at the end of summer, the creek near her house dries up, and Charlie does her best to catch the rainbow trout caught in the last of the creek, under the bridge, and take them to safety in the Big Wood River. This year she has caught all the trout except one, and now she must try to catch the last fish and take it to the river. Charlie is covered with mud from head to toe from the creek, but can she catch the last rainbow trout? Based on a true story, this children's tale follows a young girl working to save a rainbow trout from a creek that is drying up at summer's end.