About the Show
Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...
Series 9 Summary
Penny struggles with Leonard's confession that he kissed another woman when he was on his North Sea research expedition as the ninth season of the US comedy about socially clueless scientists begins
Episode 1 - The Matrimonial Momentum
After driving all the way to Las Vegas for her wedding to Leonard, Penny now faces a dilemma. At home, Sheldon doesn't know how to act after Amy tells him she's taking a break from their relationship.
Episode 2 - The Separation Oscillation
Leonard confronts the woman he kissed on a research expedition as he tries to put Penny's mind at ease about the fact that they still work together. Sheldon films a special episode of Fun with Flags.
Episode 3 - The Bachelor Party Corrosion
The guys' science skills are put to the test when they get a flat tyre during Leonard's surprise bachelor party weekend in Mexico. The girls force Penny to tell her family she has eloped with Leonard.
Episode 4 - The 2003 Approximation
Penny and Leonard announce they're moving in together, so Sheldon decides to revisit 2003, a simpler time before he had met either of them. Howard and Raj form a band to play at the comic book shop.
Episode 5 - The Perspiration Implementation
The guys take fencing lessons from Barry Kripke, but Sheldon feels awkward when Kripke expresses a romantic interest in Amy. Stuart struggles to attract female customers to the comic book shop.
Episode 6 - The Helium Insufficiency
Sheldon and Leonard struggle to find the supplies they need for an experiment. Penny and Bernadette download a dating app onto Amy's phone to find her a new boyfriend, but does she need their help?
Episode 7 - The Spock Resonance
While being interviewed for a documentary on Star Trek character Mr Spock, Sheldon struggles to suppress his emotions about his recent break-up with Amy, leaving Leonard and Penny in a state of shock
Episode 8 - The Mystery Date Observation
Sheldon enlists the help of Howard and Raj to find him a new girlfriend by posting online. When Amy is coy with the details about the guy she's dating, Penny and Bernadette decide to spy on them.
Episode 9 - The Platonic Permutation
Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Howard reluctantly agrees to volunteer at a soup kitchen with Bernadette, Raj and Emily.
Episode 10 - The Earworm Reverberation
Sheldon is driven to distraction when he can't get a familiar tune out of his head or recall the name of the song. Amy and Dave arrange another date. Howard and Raj find out that their band has a fan.
Episode 11 - The Opening Night Excitation
Sheldon seeks advice from Penny and Bernadette while planning something special for Amy's birthday. Leonard, Howard and Raj can't decide who should get their extra ticket to the latest Star Wars film.
Episode 12 - The Sales Call Sublimation
Penny gets more than she bargained for when Leonard meets a psychiatrist. Sheldon and Raj make an astronomical discovery. Howard and Bernadette can't believe how they feel after Stuart moves out.
Episode 13 - The Empathy Optimization
The gang do their best to look after Sheldon when he's ill, but after dealing with his incessant demands, rudeness and lack of gratitude, they decide to indulge in a Sheldon-free weekend in Las Vegas.
Episode 14 - The Meemaw Materialization
Sheldon is thrilled when his grandmother comes to visit, but his excitement fades when she butts heads with Amy. Raj meets a girl at the comic book shop and questions his relationship with Emily.
Episode 15 - The Valentino Submergence
Sheldon and Amy host a special live Valentine's Day episode of their internet show Fun with Flags. Leonard and Penny grapple with getting older. Howard and Bernadette find a surprise in their hot tub.
Episode 16 - The Positive Negative Reaction
When the gang find out about Bernadette's big news, they celebrate by getting together for an evening of karaoke. But Bernadette grows concerned when Howard starts to freak out over her announcement.
Episode 17 - The Celebration Experimentation
After more than nine years together, the gang finally manage to persuade a reluctant Sheldon to celebrate his birthday, so they throw him a party with a few special guests in the 200th episode
Episode 18 - The Application Deterioration
Leonard, Sheldon and Howard have problems when they file for a patent for their infinite persistence gyroscope. Raj needs some relationship advice when Emily reaches out to him after their break-up.
Episode 19 - The Solder Excursion Diversion
Sheldon makes a surprise revelation when Amy buys him a new laptop. Leonard and Howard lie to Penny and Bernadette to avoid an errand and attend a free movie screening, but Raj gives the game away.
Episode 20 - The Big Bear Precipitation
Sheldon shares a secret about Leonard when the two of them go on a weekend trip to a cabin in the country with Amy and Penny. Raj gets carried away buying pregnancy gifts for Howard and Bernadette.
Episode 21 - The Viewing Party Combustion
During a group get-together to watch television at the flat, a minor argument between Sheldon and Leonard escalates into a heated debate. Raj is smug about dating Emily and Claire at the same time.
Episode 22 - The Fermentation Bifurcation
The gang run into Penny's ex-boyfriend Zack on an outing to a wine bar, while Bernadette, who can't drink, hangs out with Sheldon for the evening. Raj introduces his new girlfriend Claire to the guys.