Ellen Tebbits lives on Tillamook Street, in the same neighborhood as Otis Spofford, Ramona Quimby, Henry Huggins, and her new friend from dance class -- Austine! At dancing school, Ellen and Austine first discover that they share the same secret and then learn that they live two blocks apart! The two of them are always together at dancing class, and like to play at each other's houses.

Austine liked to play at Ellen's house because the attic was full of such interesting things -- old clothes for dressing up, a violin with half the strings missing, piles of magazines full of coupons to send away for free samples. The basement was an interesting place, too, and the girls spent one rainy afternoon there blowing bubbles in a bucket of soapsuds with an old tire pump.

Quickly, Ellen and Austine become best friends. They do everything together, from clapping erasers to riding horses. Ellen learns that embarrassing secrets and pesky troublemakers like Otis Spofford aren't so bad when you have someone special to look up for you.