Main cast[edit]

• Johnny Galecki as Dr. Leonard Hofstadter
• Jim Parsons as Dr. Sheldon Cooper
• Kaley Cuoco as Penny
• Simon Helberg as Howard Wolowitz
• Kunal Nayyar as Dr. Rajesh 'Raj' Koothrappali
• Mayim Bialik as Dr. Amy Farrah Fowler
• Melissa Rauch as Dr. Bernadette Rostenkowski-Wolowitz
• Kevin Sussman as Stuart David Bloom
• Laura Spencer as Dr. Emily Sweeney

Recurring cast[edit]

• Laurie Metcalf as Mary Cooper
• John Ross Bowie as Dr. Barry Kripke
• Wil Wheaton as himself
• Casey Sander as Mike Rostenkowski
• Alessandra Torresani as Claire
• Christine Baranski as Dr. Beverly Hofstadter
• Brian Thomas Smith as Zach Johnson
• Sara Gilbert as Leslie Winkle
• Bob Newhart as Dr. Arthur Jeffries/Professor Proton
• Stephen Hawking as himself

Guest cast[edit]

• Jim Meskimen as a minister
• Melissa Tang as Mandy Chao
• Keith Carradine as Wyatt
• Megan Heyn as Natalie
• Patrika Darbo as Grace
• Michael Rapaport as Kenny
• Adam Nimoy as himself
• Stephen Merchant as Dave Gibbs
• Analeigh Tipton as Vanessa Bennett
• Elon Musk as himself
• Wayne Wilderson as Travis
• Jane Kaczmarek as Dr. Gallo
• June Squibb as Meemaw
• Creagen Dow as Maitre D'
• Adam West as himself
• Blake Anderson as Trevor
• Judd Hirsch as Alfred Hofstadter

Leonard and Penny elope in Las Vegas, live streaming the ceremony for friends at home. Leonard wrote a touching cosmology-based wedding vow while Penny recites 'You've Got a Friend in Me'. When they kiss after he carries her over the threshold, Penny is still bothered that Leonard kissed Mandy two years ago and is outraged to hear they work together. When Leonard and Penny return home, she goes to her apartment alone. Sheldon, confused and hurt by Amy's indecision about their relationship, insults her before all their friends watching the wedding at Howard and Bernadette's house. Amy openly breaks up with him, upon which all leave except for Howard and Stuart, who actually see the wedding to the end. Sheldon calls his mother to return his great-grandmother's ring which he had intended for Amy, but Mary tells him to wait. Sheldon briefly considers dating Mandy to hurt Amy. He is angered that Penny knew Amy was unhappy and did not defend him. A dejected Leonard cannot believe he is spending his wedding night with Sheldon, though Sheldon always expected this.

After having a nightmare of Sheldon and Penny passionately kissing, Leonard considers marriage counseling but finds it too expensive. Howard and Bernadette have long known of Leonard and Mandy's kiss. Howard kept it from Raj, as did Bernadette from Penny. Bernadette points out to Penny that the now confident Leonard is with her because he loves her, not out of desperation. During a chat with Mandy Chow, who is not attracted to Leonard and neither remembers nor cares that she kissed him, he realizes part of himself may be trying to sabotage his marriage as he thinks he is not good enough for Penny. Penny admits fearing he will leave her for someone smarter. Both agree to abandon their fears and embrace their happiness. Sheldon surprises them with a trip to San Francisco, only to say he is going too, as he bought the tickets for himself and Amy. Sheldon returns Amy's belongings, failing to make her jealous by 'accidentally' putting one of Penny's bras in the box. He records a 'Fun With Flags' episode alone, angrily using countries that separated as metaphors for Amy dumping him. Amy, furious, demands he remove the video, for Sheldon a sign she still wants him.

Raj and Howard plan to kidnap Leonard for a belated bachelor party weekend and forcefully take Sheldon, who is impressed that the van they are driving once belonged to physicist Richard Feynman, and that they plan to stay at his vacation house in Mexico. When the van has a flat tire, a stuck lug nut prevents the men from fixing it. Several scientific methods all fail to remove it, but ultimately inadvertently set the van on fire. Meanwhile, the women have a small bachelorette party at Penny's apartment. Amy reveals she has not told her family about her breakup with Sheldon, relating how her mother had her sit in a 'sin closet'. Penny pierces Amy's ears for her, and mentions she has not told her family she married Leonard. She reluctantly calls her father Wyatt, who is simply happy for her, though he upsets Penny on confessing he accidentally killed her pet pig a year ago. The women have Amy call her mother, but when Amy finds it difficult to tell her about the breakup, Penny tells her about Amy's breakup, her penis cookies, and her pierced ears. Then Amy's mother has her sit in Penny's closet.

Leonard and Penny finally tell Sheldon they have moved in together now that they are married. Sheldon is upset, but Bernadette says he should try to find another roommate, though Stuart firmly rejects her idea that he move in with Sheldon. Sheldon rejects everyone he meets and Amy refuses to live with him, as they have just broken up. Sheldon tries to pretend that it is 2003, before he met Leonard, Penny and Amy, and before he developed emotional connections to other people, fearing that Leonard and Penny, too, will eventually abandon him. For his sake, Leonard and Penny agree to split their time between apartments to be with Sheldon who begins to modify The Roommate Agreement for this purpose. Meanwhile, Stuart wants a band to play music in his comic book store for free. Raj and Howard write a filk song about Thor fighting Indiana Jones, though Emily suggests it would be better if people could dance to the music. Raj and Howard momentarily break up the band but quickly make up, playing the song at the store only to have Stuart say they should play music people could dance to.

Howard builds a machine to add mileage to the Fitbit Bernadette bought for him to track his exercise. Leonard, however, decides that the group should become more active and they take up the sport of fencing, attending a class taught by Barry Kripke. After learning that Amy is single, Kripke wants to ask her out, which upsets Sheldon. The men go to a sports bar and encourage Sheldon to move on. Sheldon randomly asks two women out and is rejected. Stuart asks Penny, Bernadette, and Amy for advice on how to attract more female customers to his comic book store and they conclude that his creepy behavior is the problem. Amy sympathizes with him for being lonely, but turns him down when he hits on her. She also rejects Kripke after he sends her a photograph of him nude. When Leonard and Sheldon return home from the bar, they run into Amy and Bernadette, leading to a chat between Sheldon and Amy, who awkwardly exchange anecdotes on their attempts to move on.

Swedish physicists are about to prove Sheldon and Leonard's super-fluid hypothesis about the universe and the men need liquid helium to conduct their experiment first. Kripke refuses to let them use any of the university's helium. Howard connects them to Kenny, a black market dealer, though Sheldon's mistrust of him almost ends the deal. At the lab, Leonard and Sheldon panic about using stolen property and pay Kenny to take it back. Kripke offers to give them some of his helium if they share scientific credit with him. Instead, they pay Kenny for helium a third time and watch Ernest Goes to Jail with him because he gets along with them. Meanwhile, Stuart tells the rest of the group he has been on two dates thanks to an app on his phone. They download it on Amy's phone much to her discomfort and make fun of the suggested men. To their surprise, a man named Dave texts Amy his thanks for the date they had last night. Amy reveals she has been on three coffee dates with men and is starting to like Dave.

Wil Wheaton arranges for Sheldon to be interviewed for a documentary about Spock, For the Love of Spock and Leonard Nimoy by his son Adam. Sheldon explains he admired the character of Spock from childhood for being unemotional and tried to imitate him. He brings upthe autographed napkin from Nimoy that he keeps with his valuables, including the engagement ring he got for Amy. His aborted proposal to Amy shocks Leonard and Penny who push Sheldon to admit he is feeling hurt. Sheldon lashes out, but decides to propose to Amy anyway for closure. From a distance, he sees her kiss another man, Dave, goodbye outside her apartment building, and leaves dejected. At home, he is upset Spock's way of life is a lie, and Leonard tells him to start focusing on the real people in his life. Meanwhile, Bernadette wants to start renovating the house, though Howard protests against changing his childhood home. Calling in her father Mike, he asks why Howard does not want children. Howard reveals Bernadette to be the one resisting parenthood. Raj theorizes she fears it because Howard acts so childish. Howard says he always dreamed of being a responsible father to make up for his own abandonment in childhood. Bernadette promises to think about it.

Amy has another date with Dave, so Bernadette and Penny decide to spy on her, dragging Leonard along. During the date, Dave reveals he is a huge fan of Sheldon's scientific work. He asks her about Sheldon the entire time, greatly annoying her. As they leave, Bernadette hits Dave's car. Initially outraged about the accident, Dave meets Leonard and is instantly starstruck. Amy ends it with Dave, who is happy to have kissed and been rejected by the same woman as Dr. Sheldon Cooper. Meanwhile, Sheldon struggles to move on without Amy, so he asks Howard and Raj to set him up with another woman since they introduced him to Amy. They post an ad on Craigslist that is filled with scientific and science-fiction brain teasers to solve for Sheldon's contact information that night. Fifteen seconds after the deadline, a woman named Vanessa shows up, sharing many of Sheldon's interests including physics, flags, and obscure languages. He does like her, but shuts the door on her for exceeding the time limit.

With Sheldon and Amy still broken up and all of his friends busy for Thanksgiving, Sheldon tries to give her tickets he bought them to Thanksgiving dinner at the aquarium, but Amy suggests they can still go as friends. Despite initial awkwardness, Amy honestly answers Sheldon's questions about her dating life, and each wants the other to be happy. They fall back into their old relationship as friends. Later, Amy tells Sheldon she is ready to be his girlfriend again. Sheldon declines, since getting over her was too difficult, but wishes to remain friends. Amy hides her hurt feelings. Bernadette, Raj and Emily drag Howard to a soup kitchen to volunteer for the day, after Howard lies about going there to avoid Sheldon. At the soup kitchen, Howard hates washing dishes, but is delighted to meet Elon Musk, the founder of SpaceX. They bond over space travel. Meanwhile, Leonard and Penny prepare Thanksgiving dinner at home for the gang. When he realizes she does not know his birthday, he proceeds to list personal things he knows about her, but accidentally reveals knowing she hates some orange lingerie he bought her, which she only disclosed in her journal. To apologize for reading it without permission, Leonard dances in the lingerie, asking Penny to post an image on her social media as punishment. Penny refuses, but Howard, Raj, Bernadette, and Emily barge into the scene in his apartment.

Sheldon is humming the melody to a song he does not know the name of, which is especially unusual since he has an eidetic memory. He spends two days obsessing over the tune and recording a log while he is still mentally sound, fearing he might be turning into a mad genius, thus annoying Leonard and Penny. Meanwhile, after getting rejected by Sheldon, Amy tries to move on and arranges another date with Dave, who struggles to contain his excitement about Sheldon. Sheldon finally realizes the song is 'Darlin' by the Beach Boys (the notes corresponding to the introduction), that the lyrics relate to how Amy made him a better man, and rushes to her apartment, interrupting her date with Dave. Dave helps Amy realise that Sheldon loves her and they get back together. Meanwhile, Howard and Raj's fan page for their filk band is liked by a person named Trent. They stalk Trent online and think he is very cool, deciding to go meet him in a café. However, they see him pick his nose and eat his own booger, causing them to run out.

After an iconic Star Wars-like opening credit crawl, the men are overjoyed to get opening night tickets to the Star Wars: The Force Awakens movie, which premieres on Amy's birthday. As Sheldon bought his ticket when he and Amy were broken up, he still wants to see it, despite Penny saying he should be with Amy. Sheldon has a dream/visitation where Arthur Jeffries' ghost talks with him while dressed as a Jedi master, and convinces him Amy is more important, leading him to tell Amy he'll spend the day with her as well as give up his Star Wars ticket to the rest of the men. Talking over birthday gift ideas with Penny and Bernadette, he shocks them by saying he is going to have coitus with Amy to show her how much she means to him. On Amy's birthday, Sheldon and Amy are nervous about having sex, but enjoy the experience more than they expected. Sheldon wants to do it again on her next birthday, which is fine with Amy. Arthur later appears to Sheldon again, asking for details about the sex, but Sheldon replies by discussing the movie, oblivious to Arthur's real question. Meanwhile, the rest of the men go to the movie with Wil Wheaton, who arrives dressed as Spock in a Star Trek uniform to spite the viewers. After the movie, the men lie back in the afterglow, much like Sheldon and Amy did.

Penny cannot find a way to make a sales call on psychiatrist Dr. Gallo. She has Leonard pose as a patient to get her in the door. Dr. Gallo disagrees with the way Leonard's mother approaches psychology. Leonard feels great talking with her. When Penny meets her, Dr. Gallo has her question why she often acts like a mother to Leonard, along with her other anxieties, such as Sheldon. She also makes Penny feels better after their talk. Dr. Gallo gives her a prescription, but not the one Penny was supposed to sell. While Amy is at a conference, Sheldon spends the day at the astronomy lab with Raj. After they discover a medium-sized asteroid, they argue about what to name it; Leonard suggests they name it after their girlfriends. Sheldon gets Raj to name it after Amy in exchange for any children Sheldon and Amy have being named Rajesh, even their daughters. Howard and Bernadette want to start remodeling the house and are excited when Stuart moves out, but are surprised when they find they miss him. Unbeknownst to them, Stuart sneaks back at night to watch them sleep.

While Amy is still away, Sheldon has recovered from the flu, but though his friends attempt to help him, his rude behavior during his illness offends them. They decide to rent a party bus to Las Vegas to get away from him. Amy admits she, too, extended her trip to avoid him, and teaches Sheldon about empathy. After Sheldon realizes what he did was wrong, he apologizes to each of his friends in turn, but his apology to Emily goes wrong when he says dermatologists are not real doctors. When Raj tries to defend Sheldon, it leads to a fight between him and Emily. Sheldon decides not to go to Las Vegas with the group as a gesture of his regret, but sneaks onto the bus with Stuart to make amends with Emily and fix things between her and Raj. Sheldon and Stuart then leave, but the others decide to let Sheldon and Stuart go with them after all.

Sheldon's grandmother 'Meemaw' visits Pasadena to check out Amy. Meemaw distrusts Amy due to their breakup and lets slip that Sheldon had planned to propose. Both Sheldon and Amy tell Meemaw how they make each other a better person, so Meemaw tells them that she won't stand in their way. On the subject of marriage, however, Sheldon tells Amy to slow down as they've just got back together and had sex. Meanwhile, Raj has a debate about Frozen with Howard, attracting the attention of Claire, a bartender working on a science-fiction screenplay for a children's film. She asks Raj to meet her for a scientific perspective on her plot. Raj wants to do this, but Howard and Bernadette warn him it could upset Emily. Raj is unsure where things are going with her, but eventually tells Claire he has a girlfriend. Claire says they can still meet as two platonic adults. However, at the meeting, Raj fantasizes about having a family with Claire.

Leonard and Penny go out to eat for Valentine's Day and realize that they are getting older after Penny is addressed as 'Ma'am'. Howard and Bernadette plan on using their new hot tub and find a rabbit floating in it. After nursing it back to health and naming it Valentino, the rabbit bites Howard, who heads off to the ER for a rabies shot. Bernadette decides for the moment not to tell him that she is pregnant. Raj finally decides to break up with Emily and then calls Claire, who has just gotten back together with her old boyfriend. Emily does not take him back, sending Raj into a depression. Sheldon and Amy host their first live episode of 'Fun with Flags'. Taking live phone calls, wherein Amy ends up speaking with Raj and Barry Kripke about their love lives, which thoroughly depresses Sheldon. Amy does get Sheldon to admit their own breakup has made them a stronger couple. They are interrupted by Penny and Leonard, who barge in dressed as Cupids, throwing confetti in an effort to feel young again.

Bernadette tells Howard she is pregnant. While he is excited at first, he begins panicking that he will be a bad parent. When Howard talks things over with the men, Sheldon is upset that a baby will change their social group. The others try to calm him down at a karaoke bar and come up with a possible way for him to make more money by expanding on Sheldon and Leonard's research and patenting the idea. A drunk Sheldon says that, because he and Howard both grew up without fathers, Howard will know how important he is to his own child. Meanwhile, Bernadette meets with the women to tell them, though Leonard texts Penny beforehand. She is worried by Howard's reaction, but Amy and Penny tell her life will be better with a child. Bernadette shocks them by admitting the baby was conceived on Sheldon's bed. After their ideas for fun all turn out to be impossible to do because Bernadette is pregnant, the men invite them to sing karaoke with them. Howard and Bernadette soothe each other's fears. Everyone takes turns singing about babies to Bernadette, while Sheldon is shocked to learn what happened in his bedroom.

When Amy plans a birthday party for Sheldon because he made her birthday so special, he is reluctant on account of a traumatic childhood experience in which his twin sister Missy and her friends lied to him that Batman was coming to their sixth birthday, thereby ruining all his birthdays thereafter. Nonetheless, he relents, and the friends hire TV's Batman, Adam West, to attend as their present. When Sheldon arrives, he is initially happy, but quickly panics and runs into the bathroom. Penny tries to talk to him and they open up to one another. He emerges to apologize to everyone, after which Amy and all assembled share a toast in Sheldon's honor. Sheldon is delighted to hear all the nice things said about him. They then receive a video call from Professor Stephen Hawking, who joins them in singing 'Happy Birthday to You'.

Sheldon, Leonard, and Howard move forward with patenting their gyroscope idea, but are shocked to learn that, as Caltech employees, they are only entitled to 25% of any profits, and that Howard, as a NASA employee, is not legally entitled to any profits. They reluctantly agree to sign, allowing Sheldon to write their own contract to share the money from the remaining 25% with Howard. Bernadette is against this, as Sheldon belittles Howard every time they try to work together. When confronted about this, Sheldon agrees to make it part of the contract that he be respectful of Howard for the purposes of the patent. Sheldon also shows his generosity by stipulating that 1/4 of his profits will go to a scholarship fund for the Wolowitzs' baby. Meanwhile, Emily sends Raj a belated Valentine's gift and wants to see him again. Raj turns to the women for advice, but decides to go through with seeing her after they say he shouldn't. On his way there, Claire calls him to say she is now single and he should see her instead, since Emily is just manipulating him. Raj drives back and forth while talking to both women, unsure of whom he should see, before choosing Emily and ultimately sleeping with her.

While Leonard and Howard work in Howard's lab, their wives join them and help with their project. After leaving to pick up more solder, the two men are invited to see a preview of Suicide Squad and decide to lie to their wives and attend. Howard spitefully texts Raj, unaware that he is in the lab with the women. Raj is ready to help the women out their husbands' lie, but the men show up with flowers and apologize. Sheldon's old laptop finally dies, so Amy buys him a new one. He does not want to dispose of the broken one and takes Amy to a storage facility, where he reveals that he has never thrown anything away, including clothes, broken electronics, and toothbrushes. Amy now feels closer to him and begins to help him let go of his past, one small step at a time. Sheldon later sends her home so that he can Skype with her on his new high-resolution laptop.

Amy persuades Sheldon to join her, Leonard and Penny for a weekend at a cabin in the woods. Sheldon is phobic to everything in the outdoors. After their hike is rained out, they play the game 'Never Have I Ever', where Sheldon exposes Leonard's extra bank account that he keeps secret from Penny. Penny gets mad, but reluctantly understands. She admits she is unhappy in pharmaceutical sales, but also does not want to go back to acting or waitressing. She resolves to stick to her job in order to be adult and pay off her credit card debt. Sheldon admits he was once arrested in a jaywalking incident, and Amy once pushed all the buttons in an elevator. Raj gets too involved in Bernadette's pregnancy by suggesting specialists and buying a huge Costco teddy bear. Howard tells him to back off, until Bernadette gets upset and wants both him and the bear back. He returns, and the three listen to the baby's heartbeat, though Raj gets a little too close again.

As the group prepares to watch Game of Thrones at the apartment, Leonard refuses to go to Sheldon's quarterly roommate agreement meeting and is further annoyed when Penny takes Sheldon's side. Amy arrives and agrees with Leonard, stating her dislike of meetings regarding the relationship agreement. On the way there, Raj constantly brags about dating both Emily and Claire, annoying Howard. Stuart shows up in costume because Howard tricked him into wearing it. The group splits up, with Sheldon, Penny, Raj, and Stuart in one apartment and Leonard, Amy, and Howard across the hall. Leonard is further upset to learn Penny goes behind his back to Sheldon to get what she wants in the roommate agreement. Amy only took Leonard's side because she is jealous of how close Sheldon and Penny are. However, all fights come to an end when Howard accidentally eats pistachios from the Mortadella sub sandwich and has to go to the hospital after an allergic reaction. He is alright. The group compare all their scheming to the characters on the Game of Thrones series. The men later make fun of Stuart riding home on a bike while still in costume.

Penny wins a wine-tasting trip at work, so everyone but Sheldon and a pregnant Bernadette joins her. Raj is still dating both Emily and Claire, but is not exclusive with either and decides to bring Claire, asking his friends not to bring up their relationship status. They meet Penny's old boyfriend Zack, who raises the potential military applications of Leonard and Howard's gyroscope system. This worries them, but Howard decides he still needs the money for his baby, so they move forward. Zack also flirts with Claire and questions why Raj is not more committed to her. Claire tricks Raj into admitting he is seeing someone else too. At home, Sheldon bores Bernadette with his love of trains and different types of toast, but she does enjoy a version of Dungeons & Dragons, in which her character is not pregnant and can enjoy alcohol, sushi, and hot tubs. She thanks him for a fun break from her pregnancy.

To avoid his mother Beverly and join the guys at a special Avengers screening and Q&A session, Leonard has Penny collect her from the airport. Penny tries to bond with her but is countered with condescending or psychoanalytical remarks. Beverly offers to interview Amy, Bernadette and partners for a new book on high-achieving couples, but when Bernadette suggests she interview Penny too and Beverly retorts 'About what?', Penny finally explodes and expresses her feelings at the insults. Beverly admits reacting to the insult of neither being invited to her son's wedding nor even being informed of it. Penny suggests holding a new ceremony for Beverly, and they at last bond. Sheldon hires Stuart to shop with Amy instead of him so he can keep his place in line for the Q&A event. Amy, annoyed, pays Stuart to yell at Sheldon, and rejects Sheldon's flowers and apology delivered by Stuart. Stuart holds Sheldon's place in line so he can apologize to Amy in person. Sheldon's experience is finally ruined when only he is upset about a man joining friends in the line ahead of Sheldon.

When Leonard and Penny announce their second wedding ceremony, conflict arises between Leonard's parents Beverly and Alfred. Sheldon has also invited his mother Mary. Beverly and Mary are still distant with each other, while Beverly and Alfred bicker. While the Hofstadters snipe at each other during dinner, Mary and Alfred bond over their dislike of Beverly and leave early, since they are staying at the same hotel. Sheldon and Leonard are later worried when neither parent will answer their phones that night, though Penny is amused at the thought that their parents are becoming closer. When Howard gets an e-mail from the U.S. Air Force about his gyroscope patent, he fears that the government is after him, due to negative portrayals of them in the media. Bernadette tries to convince him that he is paranoid, but Howard's fears increase when he sees a car following them to dinner, unaware that it is Leonard and Penny. His attempt to evade them causes him to drive recklessly, and he is pulled over by a policeman for a sobriety test.