When Harriet loses her last—and favorite—baby tooth, she struggles with saying goodbye to her babyhood.

The Welsch family attends a neighborhood party where Harriet is determined to find out why the Robinsons are so boring.

At the world's fair, Harriet meets a 14-year-old photographer who's unsure of his future—but shows Harriet how to cherish today.

Sport joins Harriet for a local scavenger hunt. But when he brings his good-luck charm to improve their chances, Harriet is skeptical.

While Harriet's parents are out, she and Ole Golly join Mr. Waldenstein for a movie date. But can they get home before Harriet's parents do?

When Ole Golly announces she and Mr. Waldenstein are getting married and moving to Montreal, Harriet tries to change her mind.

Harriet's dream of creating a post–Ole Golly life is shattered when her notebook falls into the hands of her nemesis: Marion.

The fallout from her private thoughts becoming public leaves Harriet fighting to repair her friendships—and for the return of her notebook.

With the notebook causing quite a stir, Harriet hopes a backyard trial of her peers will prove her innocence.

After Harriet makes an unexpected discovery, she comes up with a plan to right her wrongs.