High-schooler Grover Beindorf and his younger sister Stacy decide that their parents, Janet and Ned, are acting childishly when they decide to divorce after 18 years of marriage, so they lock them up in the basement until they'll sort out their problems.

Now a pre-teen, Junior has fallen head over heels for a classmate who doesn't even notice him, but does notice three other boys – a child star, a hockey player and a Boy Scout – who are rivals to Junior. This means war!

Psychotic Angela is itching to do what she does best: slaughter dozens of teenage campers. As luck would have it, the previous site of her murders has been renamed and converted into an experimental summer camp meant to bring together privileged and lower-class teens. On the day the youths are boarding the buses to camp, Angela runs over a potential camper with a garbage truck and assumes her identity. Once she has infiltrated the camp, the real terror begins.

Angela, supposedly reformed and living under an assumed surname, is working at a summer camp. However, when the campers start misbehaving, she soon reverts to her old ways.

King is a young man, but he's already a veteran of life on the streets of Los Angeles. The de facto leader of a group of teenage runaways, King acts as a mentor to troubled kids such as gay hustler Little J and junkie Greg. When Heather, a beautiful girl from Chicago, starts hanging out with King and his crew, it changes the dynamic of the gang. However, it seems as though nothing will alter their dangerous lifestyle.

《欢乐合唱团》可以说是这几年来最成功，也是唯一成功的有剧本音乐喜剧，除了剧集本身很吸引人之外，连带发行的专辑和随后推出的巡回演唱会都非常成功。并且它对于青少年之于音乐的狂热也很有影响，和《美国偶像》、《美国之声》等真人秀一样，让人感受到了音乐所带来的正能量。