Best friends and brilliant physicists Leonard Hofstadter and Sheldon Cooper are geniuses in the lab but socially challenge outside of it. Despite this, Leonard married his beautiful, street-smart neighbour, Penny. And Sheldon, after a long courtship, wed successful neurobiologist Amy. And while aerospace engineer Howard and his adorable microbiologist wife, Bernadette, explore the predicament of being married with two kids, astrophysicist Raj considers a traditional arranged marriage. As the supersmart friends solve quotidian conundrums posed by academia. Family crises and video games, their experiments in domestic bliss never fail to produce hilarious results. But all good theories arrive at a conclusion. The twelfth and final season of "television's perpetual laughter continuum comprises" 24 supercharged episodes that take comedy to the next dimension...and beyond.

University physicists Leonard and Sheldon know whether to use an integral or a differential to solve the area under a curve. But they don't have a clue about girls. Or dating. Or clothes. Or parties. Or having fun. Or, basically, life. So when a pretty blonde named Penny moves in the apartment across the hall, the guys decide to get an education outside of the classroom. Boys, you have a lot to learn.

This season, Leonard gets a girl. So does Sheldon. Howard drives the Mars Rover into a ditch. Raj woos a terminator. Gorgeous girl-next-door Penny falls under the spell of Age of Conan. And super-smart, ueberconfident Leslie Winkler reduces mere men to spineless jellyfish.

This season the Big Bang gang’s romantic universe expands. On the rebound from Penny, Leonard falls into the arms of Raj’s sister Priya. Sheldon gets a girlfriend, or rather a friend who is a girl: Amy, a dour neurobiologist who declares herself besties with Penny. Howard and Bernadette heat up. And so do Raj and Bernadette (at least in Raj’s Bollywood daydream).

Worlds collide in Season 3! A love affair with Penny has opened a big, wide, wonderful world of romance for Leonard. But Sheldon likes the world just the way it was, thank you. All of which makes for a zany comic triangle with brainy, clueless Sheldon and practical, grounded Penny hilariously vying for the role of hypotenuse.

In season five, Penny and Leonard's relationship is relaunched in full "beta test" mode, while Sheldon, Howard, and Raj discover the feminine mystique is something that cannot be easily graphed or calculated. As Sheldon makes begrudging amendments to his "Relationship Agreement" with his "friend-who-happens-to-be-a-girl" Amy Farrah Fowler, Raj contemplates an arranged marriage, and Howard is all-systems-go for both is NASA space launch and wedding to the spirited Bernadette.