Twenty-five years after the original film, Sharon Ferris [Hayley Mills] is divorced and raising her daughter Nikki Ferris [Carrie Kei Heim] in sunny Tampa, Florida. The looming move to New York City strains their bond as Nikki dreads a fresh start, especially the idea of an all-girls school in the fall. In summer school, Nikki makes enemies with Jessica Dintruff [Judith Tannen] but finds a true ally in Mary Grand [Bridgette Andersen], a girl whose father, Bill Grand [Tom Skerritt], has been widowed for four years. A plan starts to take shape: the two girls want to reposition their parents so they might meet—and perhaps end up happily married—before the move changes everything.
To engineer a meeting, Nikki and Mary secretly orchestrate a setup by sending Sharon flowers that are supposedly from Bill Grand, hoping the gesture will spark a connection. The ruse doesn’t immediately yield the desired spark—neither parent falls head over heels, and the scheme stalls. Still, the girls press on, turning to an adult ally who can help them steer the plan in a new direction: Susan Corey [Hayley Mills], Sharon’s twin sister who is married and living in California. Susan travels to Tampa to pose as Sharon and help get things started by going on a few dates with Bill, as a kind of staged beginning to a romance.
On one of the early dates, Susan, disguised as Sharon, “accidentally” bumps into Bill at a bar called the Press Box and sits through a few innings of a baseball game with him. The real Sharon, meanwhile, is puzzled when Bill visits her workplace and recounts how much fun they had together. Susan and Bill cross paths a couple more times over the next few days, while their maid, Florence [Gloria Cromwell], begins to grow suspicious of the coincidences swirling around their meetings.
Sharon isn’t naïve about the girls’ scheme, and she decides to turn the tables. She contacts Brian Corey [Alex Harvey], Susan’s husband and a Trans World Airlines pilot, to join her in a plan to stage a playful deception of their own. As Susan and Bill are out on a date, Sharon and Brian pretend to be on a concurrent date, with Sharon dressed as a different woman to keep the ruse lively and light-hearted. Susan becomes distracted and clumsy on her date, and at one point she blurts out that the man she is watching is her husband. She storms over to the other table, only to burst into laughter when she realizes her sister is the one in the wig.
With the truth suddenly exposed and the two sisters sharing a laugh, Sharon and Susan decide to shoulder the truth openly. Sharon explains that she does not have romantic feelings for Bill and suggests they simply remain friends, turning the chaotic setup into a resolution built on honesty and friendship.
A going-away party is held on the boat of Sharon’s boss, Mr. Elias [Leonard Altobell], and the mood shifts as new beginnings loom. Sharon and Bill cross paths again in the cabin, while Nikki and Mary step away to the car. The two girls slyly release the ropes and push the boat away, leaving the guests watching in a mix of confusion and anticipation as the vessel drifts farther from shore.
On the deck, Sharon and Bill finally acknowledge their connection, and Bill leans in for a kiss as the night unfolds. The scene shifts to a ceremony of a different kind: a wedding that signals a fresh start for everyone involved. Mary and Nikki are revealed as step-sisters, and the long-awaited plan to keep Nikki from moving to New York City is fulfilled, weaving the families together in a hopeful, blended future.
