Mensa-fied best friends and roommates Leonard and Sheldon, physicists who work at the California Institute of Technology, may be able to tell everybody more than they want to know about quantum physics, but getting through most basic social situations, especially ones involving women, totally baffles them. How lucky, then, that babe-alicious waitress/aspiring actress Penny moves in next door. Frequently seen hanging out with Leonard and Sheldon are friends and fellow Caltech scientists Wolowitz and Koothrappali. Will worlds collide? Does Einstein theorize in the woods?
Leonard is away at sea, so Sheldon and Penny spend time together and spill some revealing secrets. Howard comes to Raj's aid after a breakup. S7, Ep1
Leonard returns from his expedition and finds things chilly between him and Sheldon, and Howard faces questions about his masculinity. S7, Ep2
Raj puts together a scientific scavenger hunt that turns into serious, cutthroat competition that brings out the best - and the worst - in the gang. S7, Ep3
Amy ruins one of Sheldon's favourite films. Leonard discovers how to get Penny to do his bidding. Raj and Stuart get creative with dating profiles. S7, Ep4
Amy takes a job at Sheldon's university, putting their relationship to the test. Howard ends up sleeping on Raj's couch after a fight with Bernadette. S7, Ep5
Sheldon fears his major scientific breakthrough may haunt him for the rest of his career. Howard makes a grand romantic gesture to Bernadette. S7, Ep6
When Sheldon's childhood hero, Professor Proton, seeks Leonard's help with an experiment, Sheldon decides to befriend another TV science guy. S7, Ep7
Leonard fails to stop Sheldon from overreacting after a past slight comes to light, and Penny has a run-in with Raj's former girlfriend Lucy. S7, Ep8
Howard's mother has a say when he and Bernadette host Thanksgiving dinner for the gang. Penny and Leonard must deal with a mistake from her past. S7, Ep9
Amy and Leonard try to help Sheldon when his accidental scientific discovery is disproved. Howard and Bernadette open their home to Raj for a week. S7, Ep10
With Sheldon in Texas, the gang decorates for Christmas, and they each contemplate if they would have had a wonderful life if they'd never met him. S7, Ep11
Penny turns to Leonard after her guest appearance doesn't turn out well. Sheldon works on his sense of humour, and Raj practices talking to girls. S7, Ep12
Penny makes a big step toward pursuing a full-time acting career, and Sheldon is forced to take a vacation. S7, Ep13
Unable to score tickets for Comic-Con, Sheldon decides to stage his own comic-book convention, while the ladies attempt to act like grown-ups. S7, Ep14
Amy talks Sheldon into a romantic Valentine's Day getaway to Napa Valley. Leonard and Penny make an emergency visit to the vet with Raj's dog. S7, Ep15
Leonard's purchase of a new dining room table doesn't sit well with Sheldon, and Bernadette isn't happy about Howard taking another trip to space. S7, Ep16
Things turn rocky between Sheldon and Wolowitz, and Bernadette steps in to mediate. Penny is offered a movie role that may prove embarrassing. S7, Ep17
Sheldon's visit to see his mummy forces him to start addressing a new reality. The gang speculate about where they might be in 20 years. S7, Ep18
Raj wrestles with dating two women at the same time, Penny is offered a part in a trashy movie, and Sheldon can't decide between two gaming systems. S7, Ep19
Raj and Howard double-date, and the latter is flushed with embarrassment after Raj's girlfriend reveals a secret she knows about Howard. S7, Ep20