Tess Foster wants to join the school wrestling team, against her wishes of her father, the gym teacher.

Tess invites her grandmother to stay with them to try to improve the boy's manners.

When Tess and Allie are invited to a prestigious party, Tess convince the host to also invite her brother Sam.

Tess and Allie discover what true friendship is really about.

Tess feel guilty about a lie. The boys and their do) are all mad at Jack because he can't remember the parental pass code for the TV.

Tess reluctantly agrees to join the athletes at school.

Tess tries to find a date for her father.

Allie and Tess accidentally send an embarrassing photo of Sam to everyone in school, there are concerns about the administration's new neighbor, and Jack has an eyesore.

Tess and her brothers find their Christmas plans wrecked when Jack announces that he wants them all to surprise Grandma for Christmas.

Tess is set to wrestle against last year's champion. Gabe borrows Jack's glasses to look cool at a party.

Jack decides to set up a private bathroom for Tess but would have to take a second job in order to pay for it.

Since Tess has joined the wrestling team, she hasn't been on any dates with a boy. Kaylee says that girls who are on the wrestling team aren't attractive to boys. In order to prove Kaylee wrong, Tess decides to go on a date, but cannot find one.

Tess is totally blown away when she finds out that Allie starts going out with Bobby Parelli. Tess goes with the two to the movies, but she uses the opportunity to show Bobby all differences between him and Allie. However, it causes Bobby to make a sudden end with Allie and instead show interest in Tess.

Allie and Tess make it clear that Tess doesn't want to go out with Bobby. So Bobby and Tess meet secretly until Tess finds the courage to tell Allie the truth. But when a photo of Tess, Bobby and Emily Osment appears in the newspaper, it is increasingly difficult for Tess to keep her secret from Allie.

Αfter Tess started dating Bobby, she spends a lot of time with him and she always forgets Allie, which makes her angry.

After Tess breaks up with Bobby, Allie wants her to date someone else, but she keeps saying she is not ready. Meanwhile, Gabe has to pass a driving test.

When a fashion guru comes to Westfield, Tess tries to impress him by creating a contest-winning design that will get her all the way to New York.

Jack's heart is heavy when he sees how quickly his children are growing up. This makes it more difficult for Tess, who is trying not to make her 15th birthday feel like a child's birthday.

Tess discovers Sam smoking in an attempt to integrate into a group of students, so she meddles like usual. But when the meddling ends up in her getting caught with a cigarette by her dad, she organizes a secret sibling meeting with Gabe.

Jack starts dating Kaylee's mom and tells Tess to get along with Kaylee. After her efforts fail, Tess comes up with a plan to separate her dad and Kaylee's mom.

Tess and Sam are drifting into madness. They're always in a continuous competition with each other, and after fifteen years, they find it increasingly difficult to tolerate so many disputes. But then Tess receives a scholarship to another school and says yes without hesitation.

Tess and Allie are looking forward to a school trip to Italy.

When acting girly to get a cute boy to ask her to dance fails, a mysterious witch makes Tess’s off-the-cuff wish to become a boy a reality, leading Tess to discover that being a member of the opposite gender isn’t easier most of the time. Meanwhile, Spencer said that he ate all the halloween candy so now he and Jack have to go trick or treating around the block to get candy.

Every year Jack tries to get the family to pose for the perfect holiday card photo and every year his plan fails. So when the kids disappoint him yet again by botching the photo shoot, Tess feels guilty and makes them all swear to stop fighting, as the ultimate Christmas gift for dad. The strain of bottling up their frustration leads to a big fight, and Spencer, afraid his misbehavior will land him on Santa’s naughty list, runs away from home. Tess tracks Spencer down at the mall, where the Santa imparts some pretty good wisdom, helping them all enjoy a better holiday season.

After Tess is alone on Valentines Day, she and Allie come up with the idea of "Girl-entines day".