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…

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

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…

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…

Trouble arises when Amy learns Sheldon has applied for a one-way mission to colonize Mars. Also, a trip to the pet store ends in a fight for Sheldon and Amy,…

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…

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…

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…

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 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.

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

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.

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…

Leonard and Sheldon’s friendship is tested; Wolowitz’s relationship with his mom causes a threat to his masculinity.