The first season's plot centres around the relationship, and subsequent breakup, of Jen and Mark. Mark begins to pursue Laurel and they begin a relationship in the second season. The relationship is rocky due to the very different goals of the two. Mark and Laurel eventually break off the relationship but attempt to remain friends.

There are also many subplots such as Anika's manipulation of her classmates and friends, Craig's various well intentioned but ill fated social projects, Shannon's sexuality crisis, the divorce of Mark, Travis and Kat's parents and the rise and fall in the popularity of Chris. Many social issues such as prejudice, divorce, sexuality and teen pregnancy are dealt with during the run of the series.