It is based on Ann M. Martin's novel series of the same name and is about one summer in the girls' lives in the fictional town of Stoneybrook, Connecticut.

She and her co-founders (Claudia Kishi, Mary Anne Spier, Stacey McGill, Dawn Schafer, Mallory Pike, and Jessi Ramsey) vow to keep an eye on the children.

Mary Anne and Dawn, who are stepsisters, offer their parents' backyard to serve as the campsite, as long as the kids do not come inside the house and the barn (leading the club to rent a porta potty for the summer).

This leads to a summer of lies and secrets (only Mary Anne knows he is in town), while Kristy and her father re-build their bond over baseball and mouse-shaped pancakes.

Kristy tries to walk home in the rain, but is picked up by the members of the club when Mary Anne tells the other girls about what has been happening with Patrick.

Kristy then finally celebrates her 13th birthday with her friends over a melted ice cream cake that the club members had made for her.

Their rivalry lasts all summer and only ends when Jackie Rodowsky hits his first home run into Cokie, who is sitting in a tree nearby.

After the renovations and cleanup are complete, the members realize that Claudia's room is already perfect as club headquarters and they decide to give the greenhouse to Mrs. Haberman as a way of thanking her for putting up with the day camp.

"[5] Hal Hinson of The Washington Post called the film "A colorful, buoyant, loving tribute to the notion of girlfriends forever.