After leading a relatively sheltered life in private school up to this point in his life, fastidious and straight-laced briefcase-carrying Will Mackenzie faces a new reality when, following his parents' split, he is forced to attend public school for the first time in his life in his senior year. He sees it somewhat as an opportunity to insert himself among the popular kids, which he was not at private school. However, out of circumstance, he ends up in a social circle of four who are neither the social outcasts, but are nowhere near being popular. He and his new friends get into one misadventure after another in their inbetweener status. Jay Cartwright is the big talker, whose friends know his stories of sexual conquests are all made-up fantasy. Neil Sutherland is clueless to things happening around him. And Simon Cooper, who becomes Will's best friend, often makes bad choices in his primary mission to get Carly D'Amato, a childhood friend and one of the popular kids, to be his girlfriend.