Marie Grant loves to soar on the swings and glide fast down the slide with her imaginary friend, Mr. Whoo. Mr. Whoo loves Marie for who she is even though Marie walks differently, and he makes playing outside fabulous fun. But Marie and Mr. Whoo are not the only ones on the playground. Kids tease Marie for walking differently and wearing leg braces. Mr. Whoo encourages Marie and helps her find a friend her own age who likes her just the way she is.