After learning Sheldon went behind their backs to work with the military again, Leonard and Howard say Sheldon is like Thomas Edison, taking credit for others' ideas, while they are more like Nikola Tesla. Leonard and Howard bring in Barry Kripke to help create a better idea than Sheldon's, but Kripke goes to the military himself, cutting all three of them out. Meanwhile, Bernadette fears Ruchi is trying to steal her projects at work while she is on maternity leave and enlists Raj to spy on her. Though he finds proof that Ruchi may be stealing from Bernadette, Raj tries to defend Ruchi like a boyfriend would, pointing out Bernadette's hypocrisy as she would most likely have stolen from other people's projects as well. Ruchi is not happy about this and promptly dumps Raj.
As the theme of the show revolves around science, many distinguished and high-profile scientists have appeared as guest stars on the show. Famous astrophysicist and Nobel laureate George Smoot had a cameo appearance in the second season. Theoretical physicist Brian Greene appeared in the fourth season, as well as astrophysicist, science populizer, and physics outreach specialist Neil deGrasse Tyson, who also appeared in the twelfth season.
When Raj misses out on a job at the planetarium, his father says he has no confidence because Howard always makes fun of him. Raj distances himself from Howard and later gets the job. Howard is hurt by this (even after apologizing to him) and tries to make amends with Raj after his first performance at the planetarium but, when he sees him get a date, he leaves without speaking to him, thinking that the latter's life is better without him. Meanwhile, Sheldon and Amy try randomly dividing up wedding tasks, but they keep arguing. The only thing they can agree on is to get married, so they decide to just get married at City Hall. However, Sheldon decides that he wants a first dance with his new wife and they go home to plan their wedding.
President Siebert charges Leonard with distributing some extra university funds in the form of a grant. Everyone begins sucking up to Leonard. Penny is impressed by Leonard's decisiveness but unimpressed when he cannot decide between Raj, Kripke and Dr. Lee (Maribeth Monroe), an ornithologist who works with crows. Leonard, realizing that people will be angry with him no matter who he gives the funds to, eventually awards the money to himself; many crows swarm his car afterwards. Meanwhile, a stressed out Bernadette starts hiding in Halley's playhouse after work so she can have time to herself. She is eventually joined by Penny and Amy. Howard reveals to Raj that he actually knows that Bernadette has been hiding out, but is keeping quiet about it so she can have her privacy and so he can use it to his advantage.
According to Steve Holland who is the show-runner starting with this season, Wil Wheaton will return in this season since his absence from Season 10. And this has confirmed to be true since it has been stated that he reappeared in "The Proton Regeneration" (S11E6), along with Professor Proton, their first appearances since "The Opening Night Excitation" (S9E11) and "The Celebration Experimentation", respectively and a span of 43 episodes and a span of 37 episodes, respectively. Wil also returned in the 15th episode. Wil will also return for Sheldon and Amy's Wedding.
In May 2010, it was reported that the show had been picked up for syndication, mainly among Fox's owned and operated stations and other local stations, with Warner Bros. Television's sister cable network TBS holding the show's cable syndication rights. Broadcast of old shows began airing in September 2011. TBS now airs the series in primetime on Tuesdays, Wednesdays, and Thursdays, with evening broadcasts on Saturdays (TBS's former local sister station in Atlanta also holds local weeknight rights to the series). Although details of the syndication deal have not been revealed, it was reported the deal "set a record price for a cable off-network sitcom purchase". CTV holds national broadcast syndication rights in Canada, while sister cable network The Comedy Network holds cable rights.
Live+7 data is currently available only through May 5, but the top dogs will likely see little change once the final numbers are in for the traditional September-May season. The top gainer in adults 18-49 was NBC’s “This Is Us” with an average lift of 1.8 ratings points. The number two spot was a tie between CBS’ “Big Bang Theory” and NBC’s “Manifest,” with both of those shows adding 1.5 ratings points on average. These numbers do not include “Big Bang Theory’s” series finale, however, which pulled in a 3.1 rating and 18 million viewers in Live+Same Day alone on May 16.
While opening their wedding gifts, Sheldon and Amy cannot figure out the purpose of the glass shard Leonard and Penny gave them. They decide it must be a clue to a scavenger hunt to the real gift. They eventually end up in the coffee shop where they first met and find a locket in the lost and found that they think must be the real gift. The glass shard was actually a crystal chakra wand that Raj gave as a gift to Howard and Bernadette, who then re-gifted it to Leonard and Penny, who finally passed it on as a joke. Leonard and Penny find it less funny when they are given a coded thank-you note they have to use to unlock their WiFi. After making out with his employee Denise at Sheldon and Amy's wedding reception, Stuart finally asks Denise out on a date; while preparing for the date, he has a spray-tan accident, but she just finds it funny and still goes out with him. Raj is depressed everyone else has a relationship and asks his father to arrange a marriage.
In the third-season finale, Raj and Howard sign Sheldon up for online dating to find a woman compatible with Sheldon and discover neurobiologist Amy Farrah Fowler. Like him, she has a history of social ineptitude and participates in online dating only to fulfill an agreement with her mother. This spawns a storyline in which Sheldon and Amy communicate daily while insisting to Leonard and Penny that they are not romantically involved. In "The Agreement Dissection", Sheldon and Amy talk in her apartment after a night of dancing and she kisses him on the lips. Instead of getting annoyed, Sheldon says "fascinating" and later asks Amy to be his girlfriend in "The Flaming Spittoon Acquisition". The same night he draws up "The Relationship Agreement" to verify the ground rules of him as her boyfriend and vice versa (similar to his "Roommate Agreement" with Leonard). Amy agrees but later regrets not having had a lawyer read through it.
After the birth of Michael, Howard and Bernadette are unsure who should stay home with the kids. Howard decides to look after the kids one day to show he has what it takes to care for them. While Bernadette falls back in love with her job on a trip to the office, Howard is quickly tired and realizes he might not have what it takes to be a stay-at-home dad. Howard and Bernadette realize neither them is ready to give up their job.
Kunal Nayyar as Rajesh Koothrappali: A particle astrophysicist originally from New Delhi, India. Raj is initially unable to talk to women unless he drinks alcohol. Raj also has very feminine tastes and often takes on a stereotypical female role in his friendship with Howard as well as in the group of four men. Raj later dates Lucy (Kate Micucci), who also suffers from social anxiety, but it eventually ends; he later speaks to Penny without alcohol and thus overcomes his selective mutism. He begins dating Emily and their relationship later becomes exclusive. Raj also has a Yorkshire Terrier named Cinnamon.
Anu wants to have sex with Raj, but he gets so nervous in the leadup, that his selective mutism returns. Confessing to her, she is very understanding, revealing an unusual secret of her own. The next morning, he is able to have sex with her in the shower. Sheldon attempts to bond with his father-in-law, but Larry is more impressed with Howard's magic tricks, causing a jealous Sheldon to spend time with Mrs. Fowler. They bond after finding out Amy has been using Sheldon as an excuse to avoid her mother, though he does gently advise her to forgive her daughter like he would his wife. A remorseful Amy invites the Fowlers over for thanksgiving, where Sheldon and Mrs. Fowler continue to bond over Larry's ineptitude with magic.
When Mayim Bialik first learned she had to say goodbye to neurobiologist Amy Farrah Fowler, she opened up about the show ending in a blog post, asking, "And now I start to figure out what next. Where will life take me? Where will this career go? What do I want?" Up next she has a voice role in The Inspector Chronicles, a quasi-parody of Doctor Who making the leap from short to feature film. She'll reprise her role as the voice of the Inspector's time machine, known as B.O.O.T.H. Aside from that, she doesn't have any major projects lined up, aside from preparing to not see her close-knit cast the way she'd grown accustomed to. "We'll have to see what our lives look like," she told Us Weekly in early May about the chance they'll remain close. "I mean, we're all going to be on different schedules now; it's very different."