Quinn is trying to hide a pregnancy, and Finn is not the father.
At Mc Kinley High, the kids on the lowest rung of the social ladder are the members of the New Directions glee club.
Then, idealistic Will Schuester (Matthew Morrrison), who has been teaching Spanish, decides he wants to lead the singing group back to the level of its glory days, when he was one of the stars of the club as a student.
Guest stars have included Neil Patrick Harris, Gwyneth Paltrow, Sarah Jessica Parker and Kate Hudson.
Visiting musicians to the series include Britney Spears, Eve, Olivia Newton-John and Ricky Martin.
But if you had a piñata you wanted delivered, I bet he could make sure that got to them.
Season three follows the club through wins at sectional and regional competitions before winning the national show choir competition in Chicago, while its members and faculty deal with sex, relationships, sexual identity, gender identity, adoption, domestic abuse, teenage suicide, bullying, disabilities, texting while driving, college and other social issues.
Along with an impressive array of musical styles and inventive choreography, the characters also deal with complicated issues that many teenagers face today: unwanted pregnancy, missing parent, sexuality and social bullying.
At the same time, comic moments balance the darker problems.
The cast includes several Broadway stage veterans, with impressive singing talent, which led to the show's soundtrack becoming best-sellers.
The series also inspired a live concert series, 3-D movie experience and a spin-off reality program, The Glee Project, where contestants vied for a multi-episode role on the actual show.
Broadway stars Idina Menzel, Jonathn Groff, and Kristin Chenoweth have also had recurring roles.