Sheldon learns of an impending change in his living arrangements and decides to revert back to 2003, a simpler time before he met Leonard and Penny. Also, Howard and Raj…

After driving to Vegas to get married, Penny struggles with Leonard’s confession that he kissed another girl. Also, Sheldon doesn’t know how to act after Amy pushes pause on their…

Wolowitz receives some shocking news as everyone prepares for the reopening of Stuart’s comic book store. Penny teaches Sheldon how to “let it go,” but can’t follow her own advice…

As a joke, Sheldon and Penny try an experiment designed to make participants fall in love. Also, Leonard, Amy, Raj and Emily spend the evening trying to escape a room…

Sheldon pushes Leonard and Penny to choose a date for their wedding and deals with dramatic changes in his own relationship with Amy.

Friction ensues when a magazine fails to mention Leonard in an article about the paper he co-wrote with Sheldon. Also, a blackout at Mrs. Wolowitz’s home leads to a final…

When Leonard and Sheldon are invited to speak at UC Berkeley, they take a detour to try to meet an idol. Also, when Bernadette and Howard battle over the fate…

When Sheldon and Amy build a blanket fort, they come to major crossroads in their relationship. Also, Wolowitz meets the half-brother he never knew he had, and when Penny is…

When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Also, Penny is torn between auditioning…

Wolowitz questions his engineering abilities when he and Sheldon can’t get a toy drone to fly. Meanwhile, a cancelled flight nearly prevents Leonard from giving the commencement address at his…

Personalities collide when Sheldon and Leonard’s mothers finally meet. Meanwhile, Howard finally decides to “man up” and do his fair share of the housework – but not without a little…

During their weekend in Las Vegas, Bernadette and Amy accuse Penny of being a buzz kill. The guys try to invent the next big thing.

Leonard and Howard turn to Raj for help in dealing with a work emergency when they nearly come to blows after blaming each other for a potential disaster at the…

Wolowitz tries to distract Raj, who is anxiously awaiting data from a space probe he helped launch. Meanwhile, Sheldon and Leonard go dress shopping with Penny and Amy.

Leonard and Sheldon publish a paper which is widely accepted except for comments from an internet troll. Meanwhile, the girls reminisce about embarrassing incidents from their past.

Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel deep underground. Leonard and Penny seek…

The gang tries to help Sheldon when he becomes stuck in a rut at work by increasing his anxiety level. Howard teases Raj with a new game called “Cinnamon or…

The guys try to help Penny out of an awkward work dilemma, when a smitten doctor shows up at her door after her flirtatious sales techniques work a little too…

When the gang recreates a high-school prom night on the roof of the guys’; apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj’s parents’ impending divorce causes Howard and Bernadette to work on their own…

While Sheldon says a tearful goodbye to the final installment of “Fun with Flags”, Leonard, Howard and Raj search for something significant in a dead professor’s research. And Bernadette is…

Leonard and Amy make an unexpected trip to Arizona to fetch Sheldon; Penny interviews for a job at Bernadette’s company; Stuart’s relationship with Mrs. Wolowitz disturbs Howard.

When Sheldon must teach a class, Howard decides to take it. Amy takes advantage of the tension between Penny and Bernadette.

Wolowitz feels nervous when he is asked to throw the first pitch at a Los Angeles Angels game. Penny and Leonard want to prove Sheldon wrong after he says he…

Raj’s honesty comes back to haunt him when his new girlfriend is unfriendly to Penny. The guys think about becoming part owners in Stuart’s store.

Leonard buys a dining room table and it causes Sheldon to reevaluate the changes in his life. Meanwhile, Wolowitz is offered a chance to go back to space and Bernadette…

Bernadette tries to negotiate peace between Sheldon and Wolowitz; Penny receives an embarrassing offer; Raj wants Amy to write to a woman on his behalf.

When Sheldon visits his Mom in Houston, he is forced to confront a new reality. Meanwhile, Raj’s ‘Murder Mystery’ party starts some fights within the gang.

While Raj is wracked with guilt when he tries to date two women at once, Penny wrestles with whether to take a role in a cheesy movie and Sheldon is…

Sheldon faces a personal crisis after deciding he’s wasting his time with string theory. Meanwhile, a double date between Raj, Emily and the Wolowitzes ends in embarrassment for Howard.

To prepare for a date with Emily, Howard acclimates Raj to horror movies. Penny and Sheldon are upset when they discover Amy and Bernadette lied to avoid hanging out with…

As the gang celebrates Star Wars Day, Sheldon discovers he is having difficulty dealing with the death of Professor Proton.

A bad day causes Penny to reevaluate her life choices – including Leonard. Meanwhile, Howard and Bernadette struggle to care for Mrs. Wolowitz, and Raj gets relationship advice from Sheldon.

Sheldon get upset about his career, the destruction of the comic book store and Leonard and Penny’s future living arrangements. Howard and Bernadette can’t keep hold of a carer for…

Amy starts working at Caltech which causes friction with Sheldon. Howard agrees with Sheldon who mentions this to Bernadette causing a big fight for the Wolowitzes.

Sheldon’s latest scientific breakthrough leaves him feeling like a fraud; a romantic gesture between Howard and Bernadette causes Penny to up her game with Leonard.

When Professor Proton asks Leonard for help with an experiment, Sheldon retaliates by befriending Proton’s rival, Bill Nye.

When a mistake comes to light, Sheldon makes Leonard walk a mile in his shoes; Penny decides to confront Raj’s ex.

Sheldon protests when the gang drags him to Mrs. Wolowitz’s house for Thanksgiving. Meanwhile, Penny and Leonard must deal with a mistake from her past.

Leonard and Amy help Sheldon cope with the shame he’s feeling after his accidental contribution to science is disproved. Meanwhile, Raj must stay with Howard and Bernadette for a week.