Conflict arises when two sisters, Kat and Bianca, start a new high school with two very different attitudes -- Kat, is an independent spirit and doesn't care what other people think, while Bianca is determined to climb the social ladder.
Bianca overhears plans for a party and enlists Cameron to help her the address to up her social status. Kat finds out she and Patrick like the same band and he invites her to a concert. Both Stratford sisters sneak out of the house but neither of their nights turned as planned. Bianca and Cameron can't find the party and Kat has a romantic moment with Patrick ruined when Bianca needs rescuing.
When Chastity spots Bianca and the math teacher together, the rumor quickly turns into that Bianca is having an affair with a teacher. Cameron is hurt when he hears the gossip and is dismayed to find out that Bianca thinks he's gay.
After realizing how hypocritical it is for her to drive a gas-guzzling car, Kat decides to convert her car to biodeisel fuel and enrolls in the autoshop class. The boys in the class bet on how quickly Kat will give up but she bets on herself. Chastity makes a deal with Bianca: if she helps Joey raise his chemistry grade so he can play football, Chastity will allow Bianca on the cheerleading squad. However, Bianca ends up encouraging Joey's modeling dreams instead, much to Chastity's annoyance. Meanwhile, Cameron tries to figure out how to get Bianca's attention.
Bianca and her friend Dawn ask Cameron for help in setting up a web reality show to raise money so they can afford to hang out with Chastity. It doesn't take long before the girls realize that to get more viewers, they have to act sexy for the cameras. After Kat complains about her English teacher's easy grading, she succeeds in getting the grading policy changed. However, her new grade causes Kate to make tough realizations about herself. Patrick advises Cameron to show Bianca he is capable of protecting her so Cameron tries to keep a watchful eye on her reality show.
Bianca is excited to be asked to the Fall Fling by Beau Bradley, the captain of the soccer team. Since she can't date until Kat does, she convinces Patrick to take Kat to the dance and to Kat's surprise, he agrees. Meanwhile, Cameron overhears Beau bragging about his plans to seduce Bianca and resolves to sabotage her date. Unfortunately for both of them, neither Stratford sister's date goes as planned. Bianca finds out about Cameron's sabotage while Patrick gets arrested at the school dance.
When Walter goes out of town, Bianca convinces a reluctant Kat to throw a party to increase their social status. Patrick stops by and attempts to apologize but Kat refuses to listen to him. Angry, Patrick mocks Kat for being perfect. After he leaves, Kat decides to let loose to prove she's fun and puts Bianca in charge of the party, which becomes increasingly out of control. Cameron confesses his love for Bianca, but she gently rejects him. Bianca comforts Joey after he gets into a fight with Chastity and they two kiss, but quickly agree it was a mistake.
The second season starts exactly where the first one left off... Kat and Patrick have just been suspended for skipping school and Bianca is in a critical situation with Chastity, the much feared head-cheerleader, because of her secret relationship with Joey, Chastity's ex-boyfriend. Things take a sudden turn when Chastity finds out about Joey and Bianca's relationship and Kat and Patrick are forced to return to Padua High in order to allow Kat to take a test...
Walter forces Kat to invite Patrick over for dinner to scare him off, but his plan backfires when Patrick pretends to be someone he's not. Bianca gets the cold shoulder from Chastity and her followers after discovering she and Joey are dating.
On a night of official first dates, Bianca worries that Joey expects them to have a physical relationship. Meanwhile, Kat is unsure if she and Patrick are on a date until he offers to cover their dinner bill by having them run out on it.
Kat tries to convince the student government to pass a meatless lunch initiative, with some help from a new British student named Blank. Bianca sets Cameron up with one of their classmates in attempt to regain his friendship.
Kat goes on a date with Blank after Patrick downplays their relationship. Bianca has second thoughts about inviting Cameron and Dawn to join her and Joey on a double date when she finds out they are going to a make-out movie.