When Mallory is appointed to the Fern Falls Elementary School Environmental Committee, which is deciding on class projects for the upcoming Green Fair, she rapidly succeeds in alienating her classmates, friends, and family by her overzealous efforts to save the planet.
Mallory enters fourth grade with high hopes for her best year ever, but instead she starts by breaking the teacher's rules and then feels left out when her best friend likes the same boy she does.
When Mallory cannot decide what to be on Career Day, it makes her feel like she is not good at anything and she ends up telling a lie that quickly gets out of control.
After moving to a new town, eight-year-old Mallory keeps throwing stones in the "Wishing Pond" but things will not go back to the way they were before, and she remains torn between old and new best friends.
Nine-year-old Mallory turns to her diary to sort through her emotions when she finds out she has a secret admirer and her two best friends' parents may be getting engaged.