Scott falls for the new girl in school, Laurel. Mark deals with his parents breakup and impending divorce, his own suspension from school and the disappearance of his little brother. Anika declares war on Laurel after a nasty comment about her wardrobe.

Cat and Mark try to find their missing little brother. Scott attempts to ask out Laurel. Anika spreads rumours about Laurel. Mark and Laurel meet for the first time. Jen finds Travis, Mark's little brother sleeping in her car. Gil accidently insults Chris. Erin spies Mark and Laurel having coffee together. Cat busts Mark on his email from Laurel.

It's Mark and Jen's six-month anniversary and she plans on having sex with him. When Mark and Laurel are spotted hanging out, Anika and Erin spread rumors about them which hurts Jen and leads Scott feeling betrayed. Laurel apologizes to Jen and confronts Anika and Erin, making them hate her even more. Laurel and Shannon meet. Scott gets drunk and embarasses himself in front of Laurel. Jen and Mark have a romantic anniversary but she feels she's not ready to sleep with Mark who says it's fine. Later that night Cat spies Mark exchanging emails with Laurel.

Mark misleads Jen while falling for Laurel. Scott meets Brenda, the girl of his dreams. Cat reveals to Jen that Mark has been emailing and talking with Laurel behind her back. Erin pines over Chris, who's more interested in Anika. Jen reads Mark and Laurel's emails.

After their illicit kiss, Laurel tells Mark she can't be with him when he's still with Jen. Mark tells Laurel he will break up with Jen. While feeling she may be losing Mark, Jen contemplates having sex with him in order to keep him. Scott throws an Equinox party. Craig leads a one-man protest at the Cafe Java but when he chains himself to the table and insults Maggie, she leaves him there overnight. When Anika hears the ""torrid affair"" rumours going around about her, Erin tells her it was Laurel who started them (when really it was a jealous Erin). Laurel and Jen work uncomfortably on a school project together. Mark goes over to Jen's to end things with her but they end up having sex. When Mark falls asleep, Jen is left looking very unsure of herself.

Mark and Jen deal with the aftermath of their night together. Scott wonders if Brenda really likes him. Chris vehemently pursues Anika in order to fulfill his bet with Gil. Craig tries to live down ""his little accident"" at Captain Java's. Mark strings Laurel along as he tries to come to grips with his feelings for Jen. Laurel's photo of a shirtless Mark gets passed around the school. A hurt Jen ""subtly"" mentions her budding sex life with Mark to Laurel. Shannon warns Mark of the repurcussions of his situation. Chris and Anika have a date where he tries to go too far. Shannon and Jen have a fight over Mark.

Anika completely blows off Chris. Shannon attempts to mend fences with Jen. Erin tries to get to the bottom of the Chris and Anika incident. Scott is impressed by Brenda's embracing of his ""religion"" and tries to live up to her expectations. Erin, in an attempt to sway Chris's interest in Anika, tells him Anika is a virgin. Unfortunately for Erin, this only makes Gil and Chris's bet rise. Laurel ends things with Mark for good. When Mark learns his dad is cheating on his mom again and has left, this encourages him to solidify things with Jen.

Brenda and Scott go on their first real date...to her church youth group. Mark and Jen's sex life becomes the talk of the school when Laurel mistakenly mentions something to Craig, while his sister Erin is nearby. Craig tells Shannon about his endangered frog project. Chris apologizes to Anika, who softens towards him, but is completely unaware of his bet with Gil, unlike Erin who reveals to Chris that she knows. Mark attempts to mend his friendship with Laurel but is shot down. Mark and Jen try to determine who told about their love life and Jen falsely accuses Laurel when it was really Shannon, Jen's best friend.

Erin and Chris go out on a date, but to Erin's disappointment, all Chris really wants is Anika. Laurel tells Jen about her and Mark which causes Jen and Mark to argue about Laurel. Scott asks out Brenda. Craig and Laurel work on a Save the Frogs campaign.

Anika and Chris go out on a date. Scott buys Brenda underwear but rethinks it before he gives it to her. Mark tries to make up with Jen. Mark, Cat and Travis try to cope with their parents' impending divorce. Chris tells Erin to back off when she continues to come on to him.

Mark tells Jen the whole truth about him and Laurel. Anika learns about the bet that Chris and Gil have going on her. Erin is once again rejected by Chris. Anika and Erin declare war on Chris after they mend their friendship. After Chris's rejection Erin is led straight into the waiting arms of Gil.

Jen breaks up with Mark. Erin blows off Gil after their makeout session. Chris spreads rumours about Anika as does Gil about Erin. Cat distributes teacher evaluations. Shannon and Laurel decide to be friends. Jen's brother Derek gets arrested. Scott wants to change his relationship with Brenda.