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 Bloom

Special guest cast[edit]

• Howie Mandel as himself
• Buzz Aldrin as himself
• LeVar Burton as himself

Recurring cast[edit]

• Carol Ann Susi as Mrs. Wolowitz
• Pasha Lychnikoff as Dimitri Rezinov
• Mike Massimino as himself
• Margo Harshman as Alex Jensen
• Wil Wheaton as himself
• Casey Sander as Mike Rostenkowski
• Regina King as Janine Davis
• John Ross Bowie as Dr. Barry Kripke
• Kate Micucci as Lucy
• Bob Newhart as Dr. Arthur Jeffries/Professor Proton
• Stephen Hawking as himself (voice)
• Brian Posehn as Dr. 'Bert' Bertram Kibbler

Guest cast[edit]

• Jan Hoag as Lilian
• Ken Lerner as Dr. Schneider
• Janelle Marra as Claire
• Ryan Cartwright as Cole
• Meagen Fay as Mrs. Rostenkowski
• Dakin Matthews as Santa
• Matt Battaglia as Officer Reynolds
• Josh Brener as Dale
• Briana Cuoco as Gretchen
• Riccardo LeBron as Tom

Howard's mother, furious to learn he plans to leave her for Bernadette, calls him at the ISS. To pacify his mother, who wants him to stay, and Bernadette, who doesn't, he lies to both. Meanwhile, Sheldon invites Howard-less Raj to his second anniversary with Amy to outsource to the Indian any romantic activities the Relationship Agreement demands of him. Amy forces Raj to leave, so he crashes on Leonard and Penny's date. Leonard, unlike Penny, wants to discuss their relationship and resents Raj's intrusion, but has to accommodate him for Penny. When a drunk Raj demands Penny declare her love for Leonard, Raj is ejected from the apartment and goes to the comic book store, where he and Stuart bond over a nightcap and plan to meet up the next evening. Elsewhere, Amy's flirtatious gestures are lost on Sheldon; a hurt Amy tries to abandon their date. When he demands she return to drive him home, she says she will break up with him unless he says something romantic. He responds with a stunningly romantic soliloquy which she finds incredibly touching until he admits quoting it from the first Spider-Man movie.

Whilst sorting out Bernadette's wedding gifts, Penny confesses being unsure of her feelings towards Leonard, and is worried she might break up with him again. She asks Bernadette and Amy not to mention this to Leonard; however, Amy tells Sheldon, who cannot keep the secret but holds back from telling Leonard. That night he wakes Penny in her apartment and tells her never to hurt his friend Leonard. The next day, when about to talk to Leonard about her doubts, she looks into his sad face and sleeps with him instead. Later, she insists she's fine with where they are going, as they aren't getting married. Meanwhile, Stuart joins the gang on Sheldon's condition that he act like Howard whom he is replacing as Raj's friend, so he must eat Raisinets at the movies and play the same cards as Howard during Mystic Warlords of Ka'a. Stuart and Raj later visit a bar to meet women, reminiscent of Howard and Raj's friendship. Elsewhere, on the ISS, Howard is bullied by co-astronauts Mike Massimino and Dimitri Rezinov. Bernadette has him stand up to them, but they drug him and draw a mouse face and his nickname Froot Loops on his face.

Sheldon has his childhood scientific notebooks sent from home, hoping to discover Nobel Prize material in them. Having no time to read the notebooks himself, he hires attractive female grad student Alex Jensen to do so. When Amy finds out about Alex, she is jealous and inspects Sheldon's office despite Penny's insistence that Alex has no interest in him. Amy and Penny later see Alex flirting with Leonard in the Caltech cafeteria, now making Penny jealous. Amy points out that though Penny is unsure of her feelings for Leonard, subconsciously the thought of him with another woman bothers her. Penny gradually realizes Amy may be right. After finding an elementary school project of Sheldon's with Nobel potential, Alex visits him at home, again flirting with Leonard, whereupon Penny drags him to her apartment for sex. Meanwhile, a homesick Howard wants to return to Earth as soon as possible. When the return Soyuz capsule is delayed, he suffers anxiety attacks and 'space dementia' (i.e. he talks nonsense). The other astronauts give him a sedative which relaxes him but also makes him remove his pants and windmill in microgravity.

After they lose badly to Penny and Amy at Pictionary and Penny declares she can beat them at anything, Sheldon and Leonard challenge the women to a series of games. Meanwhile, Howard returns to Earth and expects a grand welcome from friends and public, but only Bernadette greets him at the airport, the grand public welcome being reserved for Howie Mandel. The couple go to Bernadette's apartment to enjoy their 'honeymoon' which is cut short when Bernadette quickly falls asleep, having taken Benadryl for her cold. Howard leaves for his home, where he is shocked to discover his mother having an affair with his dentist. At Raj's apartment he finds Stuart now stays with Raj and has replaced him as Raj's best friend, both even planning to go to a Sound of Music singalong. He leaves for Leonard and Sheldon's apartment, but immediately exits when Leonard, Sheldon, Penny and Amy, still engaged in their contest, shoo him away. He finally ends up alone in a diner, where he realizes he caught Bernadette's cold.

Stuart and Raj organize a Halloween costume party at the comic book store. Amy and Bernadette will go with their partners, but Penny dislikes parties at the store. Amy and Bernadette then persuade her to show interest in Leonard's activities just as he shows interest in hers despite not liking them. Taking their advice, she visits Leonard's lab, is fascinated by his work, is turned on, and has sex with him there - and whenever she visits his lab or he shows how smart he is, as at the party. Meanwhile, Sheldon and Amy argue over pair costumes, compromising between Amy's preferred Raggedy Ann & Andy and Sheldon's R2-D2 & C-3PO to go as Raggedy Ann and Raggedy C-3PO. Elsewhere, Howard talks endlessly about his space mission, boring his friends. Before sex, Bernadette forbids all space talk, so he boycotts the party. She drags him along anyway; he lashes out at Raj for having him silenced. Bernadette confronts Howard, who reveals that without space he is 'just...Howard Wolowitz'. She says she fell in love with 'just...Howard Wolowitz'; they kiss. Raj later sends him a video of Buzz Aldrin boring children by endlessly mentioning his Moon trip, and Howard finally realizes his mistake.

Penny rejoins community college in a bid to clear history and finally graduate. She keeps this from Leonard, who would get very excited, but on Bernadette's and Amy's advice she tells him anyway. That night, Leonard reads Penny's homework paper on slavery. It is so bad that he rewrites it entirely, showing her in the morning, but she is angry and refuses to accept it, saying she will do all her college work unaided. Later, Penny shows Leonard her B- for her own version and mocks him for thinking her not smart enough. However, Bernadette and Amy had helped her rewrite the paper. Meanwhile, Sheldon starts playing Words with Friends online with Stephen Hawking, winning almost every game. Sheldon is distraught when Hawking stops playing, thinking he stopped after persistently losing. The next day Hawking resumes playing with Sheldon, who purposely loses to ensure Hawking keeps playing. That night, Hawking phones to mock him for losing. Hawking asks 'What do Sheldon and a black hole have in common?' and tells him, 'they both suck'.

Sheldon invites Wil Wheaton for a special Fun With Flags podcast about Star Trek flags. Wil and Amy don't get on, so she demands Sheldon ask Wil to go. Sheldon refuses, so she leaves in a huff. After failing to make Amy respect Wil, Sheldon admits his relationship concerns to Penny at the Cheesecake Factory bar. She chides the Texan Sheldon for not standing up for Amy when Wil insulted her, and mischievously gets him drunk on Long Island Iced Tea. He visits Wil and tells him Texan style to apologize to Amy. Wil, surprised by this drunken behavior, does apologize, shortly before Sheldon vomits in the shrubs and comes to his senses. He and Amy, now reconciled, reshoot the podcast with LeVar Burton as the special guest, but Amy cannot get on with him either. Meanwhile, Howard moves into Bernadette's apartment after she reminds him he promised to move out of his house on returning from space. While unpacking at Bernadette's, he finds his old magic set and reminisces on performing magic tricks to cheer up his mother after his father left them. So a sympathetic Bernadette insists on them sleeping over at his mother’s house from time to time to remind her that she is not alone.

Leonard is jealous of Penny's British classmate Cole who works with her on an oral class project, afraid Cole is hitting on her. Confronting him on the staircase, he tries to frighten him off Penny, unaware he is uninterested. She overhears them and is furious at Leonard's lack of trust. In the Caltech cafeteria, Leonard discusses his problem with Alex, who flirts with him, unbeknown to him. He later tells Penny of his insecurity about other men hitting on her, and she finally confesses her love for him. Meanwhile, Howard and Raj wonder what Sheldon does from 2:45 to 3:05 pm daily. They see him enter a storage room in Caltech's basement. They break in at midnight to find only the number '43' on a chalkboard. To discover its meaning, Howard installs a Mars Rover camera to spy on Sheldon. Finding the camera, he fakes a video of himself in the room under attack by an alien creature after he opens a small wormhole to find life in the 44th parallel universe, the first '43' being lifeless. He admonishes them for spying and reveals he relaxes in the room from his difficulties in daily life, but will not explain '43'. The audience see Sheldon playing with a hacky sack in the room: '43' is his maximum number of consecutive hits.

Howard buys a new car from his space mission money and is assigned Sheldon's unused parking spot. Despite not owning a car or even knowing how to drive, Sheldon wants it back and begins a bitter feud with Howard. Sheldon takes Howard's Iron Man helmet and sits naked in his car; Howard takes Sheldon's framed diploma and sits naked on his spot, also using Sheldon’s laptop to gloat. The feud eventually draws in their partners, Amy and Bernadette supporting Sheldon and Howard respectively. Amy helps Sheldon rename the parking spot and parks her car there; Bernadette scratches it and has it towed away. Penny is caught in the middle when Amy swings her heavy handbag at Bernadette (who ducks), accidentally breaking Penny's nose. Raj finally ends the feud by mediating an agreement that Howard keep the parking spot until Sheldon learns to drive or gets a Batmobile. Sheldon & Amy and Howard & Bernadette reconcile at The Cheesecake Factory, where a battered Penny retorts 'Yeah, everybody's happy. Great!' Finally, Sheldon takes his cushion to the dry cleaner's, as a naked Howard sat on it during the feud; and also takes the opportunity to sell his laptop for the dry cleaner’s son to use.

Howard and Bernadette have dinner with her parents. He cannot start even a mundane conversation with his father-in-law as they have nothing in common. Bernadette asks her father to take Howard fishing to bond with him, and Howard and his father-in-law reluctantly accept. Howard, like Leonard and Raj, has no idea how to fish, so expert Penny teaches them the disgusting details. On the morning of the fishing trip, Howard and his father-in-law both admit their wives forced them into it. This actually bonds them, as they now share common ground (successful careers but dominating wives), and instead of fishing they visit the Palm Springscasino. Meanwhile, Amy comes down with flu. Sheldon reluctantly takes care of her, as their Relationship Agreement stipulates that either partner take care of the other when sick. Amy enjoys Sheldon's care as he never otherwise shows his caring and loving side. On recovering she feigns sickness so his care will continue, a lie exposed when Sheldon, concerned at Amy remaining sick despite his efforts, has her cheek swab cultured in a lab, revealing her recovery. Though he is reluctant to hurt her by doing so, she then enjoys him spanking her as a punishment.

The men and Stuart play Dungeons and Dragons without the women. Dungeon master Leonard sets up a Christmas theme where players must rescue Santa Claus from a gang of ogres, to Sheldon's chagrin as he hates Christmas. Raj's character dies early on, so he joins Penny, Bernadette and Amy for girls' night at a bar. They want to find Raj a partner. He is rejected by someone who just split with her partner; Raj laments remaining single despite otherwise being successful. The women sympathize, Amy even sharing her experiences of loneliness with him. This comforts him but also draws him to Amy, the only woman in the gang to whom he was not yet attracted. In the game, meanwhile, Sheldon paralyses Howard's and Stuart's characters in Santa's dungeon, berating Santa for not bringing Pop-Pop (Sheldon's maternal grandfather, the only family member to encourage his scientific pursuits) back to life, his childhood Santa wish. He abandons Santa to be eaten alive by the ogres. Sheldon later has a nightmare about Santa, who is sorry he can bring nobody back to life, but has a present for Sheldon. Anticipating a train set, he wakes in panic when Santa fires a cannon at him.

Alex invites Leonard to accompany her to Kip Thorne's lecture on quantum foam. He declines, having a date with Penny that day, so Alex offers to talk about the lecture 'over dinner'. Realizing Alex is hitting on him, he is flattered at attention from two attractive women at once despite his commitment to Penny. When Sheldon finds out, he is unhappy: his assistant Alex should devote her time to him. On Bernadette's advice, Sheldon talks to Alex about the issue, but his sexually inappropriate language leads her to file a sexual harassment complaint with the HR Department. Sheldon inadvertently infuriates the Afro-American HR Admin Janine Davis with racist and misogynist remarks. To rechannel her anger he implicates Leonard, Howard and Raj in other misdemeanours; she calls them in too. Sheldon must take an online sexual harassment seminar but, unwilling to waste time on such 'nonsense', has Alex complete it. Meanwhile, Leonard plays his cello to apologize to Penny and denies feelings for Alex, assuring Penny she is his only one. Later she says she can now cope with her insecurities: she dons thick-rimmed glasses to look like a scientist, turning Leonard on like crazy.

Leonard drives the other men to the BakersfieldComic-Con, making an unscheduled stop at Vasquez Rocks where Star Trek: The Original Series was filmed, to photograph themselves as Star Trek: The Next Generation characters, but someone steals Leonard's car with their clothes and phones. The four, stranded in the Californian desert without regular clothes and with no means of transport or communication, try to hitch a ride to Bakersfield, but no-one stops for them. They walk to a nearby diner where they report the theft to a police officer. Demoralized, the four skip Comic-Con and return to Pasadena in a car hired by Howard's mother. Meanwhile, the women wonder why the men like comics and superheroes, stuff they believe to be for kids only. To understand why, they buy comics at the comic book store to read in Penny's apartment. To resolve a heated argument over Thor's hammer Mjolnir, they then read Leonard and Sheldon's comics in their apartment. In a final scene, two car thieves enjoy the interstate highway quiz Sheldon programmed into Leonard's car navigation system.

Howard and Raj order customized action figures of themselves but receive highly unrealistic models. They then buy a used 3D printer for $5000 to make precise figures of themselves and Bernadette. She is delighted with the figures of Howard and herself until she hears how much Howard paid for the printer. She removes Howard from their joint account to teach him the value of money; he sells his half of the printer to Raj. Meanwhile, Sheldon and Kripke are forced to work together on a fusion reactor project. To Sheldon's dismay, Kripke's work is far superior and more advanced than his. He is so upset he even allows Amy to hug him. Kripke confronts him over his poor work, but thinks incessant sex with Amy is the cause. Sheldon surprisingly supports this erroneous theory to prevent colleagues discovering he is not the smartest person in Caltech. That evening he shocks Penny with an incredible revelation: it's a 'possibility' that he could one day have a physical relationship with Amy.

Leonard is reading Harry Potter and the Half-Blood Prince but Sheldon spoils the ending. After a heated argument, Leonard leaves their apartment and moves in with Penny. She is uncomfortable with this but cannot persuade him to move back. Amy, discovering Leonard has moved out, wants to move in with Sheldon, making him uncomfortable. Later, Penny and Sheldon comfort each other over their similar predicaments and decide to tell their partners the truth. When Sheldon tells Amy to leave she is incensed. He is scared and says Leonard might return since Penny does not want him living with her. A brief spat between the four ensues. A dejected Leonard moves back to Sheldon, who thereupon spoils the plot of a The Walking Dead episode. Amy, angry at the men, considers moving in with Penny, making her uncomfortable again. Meanwhile Howard, joining Bernadette and her colleagues on a Las Vegas trip, asks Raj to check on his mother, depressed since splitting with her dentist boyfriend. Raj, noting her depression, stays the night. She pampers him just as she did Howard, and hides his clothes and car keys to prevent him leaving. When he tries to escape from Howard's bedroom window, she pulls him back in.

On Valentine's Day, Leonard & Penny share a dinner date with Howard & Bernadette, who are in a foul mood as she hid his Xbox when he played Assassin's Creed instead of doing the laundry. Leonard & Penny are happy until she sees an ex-boyfriend propose to a girlfriend, triggering an argument with Leonard who later confronts her for ruining their date: she fears he will one day propose before she is ready. He suggests she propose to him when ready; he will not propose again. Meanwhile, Sheldon has Alex buy a Valentine gift for Amy. Alex buys three: a harp-shaped music box with Amy's favorites; a map of The Canterbury Tales journeys; a signed print of a brain cell drawing by Santiago Ramon y Cajal. He picks the print but keeps it. Amy suggests celebrating as he'd wish: no romance or gifts; a pizza; a Star Trek or Star WarsDVD. Touched, he makes her his emergency contact. Her delight turns to annoyance at frequent work interruptions to tend his hypochondria. Elsewhere, Raj and Stuart, both without dates that day, throw a store party for fellow singles, where Raj orates that singles are not truly alone, having one other - but when guest Lucy praises his speech, he asks her out for coffee, derides singles, and leaves with her.

Raj and Lucy have coffee after the previous episode. Lucy, scared by his questioning, feigns going to the bathroom to escape their date. Raj is so hurt that he stays in his apartment, feeling incapable of any dating, and refuses to go to work or hang out with friends. When Howard confronts Lucy over her behavior, she gives him her phone number for Raj. Howard then visits Raj at his apartment to give him the number, where he is wearing just a pair of white briefs and Uggs. Initially he has no interest in seeing her again, but later relents. Lucy visits him to apologize for walking out of their date, revealing she is very shy and uncomfortable around people she does not know, but is working on it. Pleased at this, he admits his selective mutism, which she cannot believe, though she agrees to another date to find out. Meanwhile, Sheldon's special guest for a Fun with Flags podcast about the Flag of Nebraska is Penny, who also coaches him on his body language. In a webcam chat, Amy later says he should thank Penny for helping with his podcast. When he does so, she invites him to her class play A Streetcar Named Desire. On Amy's advice he reluctantly agrees to attend, with Amy and Leonard. The play is a success, Penny's strong performance impressing even Sheldon.

As part of their Caltech contracts, Leonard, Sheldon and Howard must serve on a committee that promotes science among young women. Neither Sheldon nor Howard are interested, but on Leonard's cajoling, Sheldon suggests focusing on middle school girls and inspiring them to pursue science after completing school. They implement their ideas at Howard's old middle school but cannot enthuse the girls for science, so Sheldon calls Amy and Bernadette, both scientists, to talk to the class by phone about careers in science. The women have meanwhile skipped work to go to Disneyland and be made up as Disney princesses. All want to be Cinderella, but Bernadette insists she be Cinderella since she planned the trip and drove them there, so Penny is Aurora from Sleeping Beauty and Amy is Snow White. Back home, Bernadette's and Penny's costumes turn on their partners. Amy, still in her Snow White costume, wants Sheldon to awaken her with a kiss, but he is tired and uninterested. Elsewhere, Raj and Lucy have a 'texting date' in the library: they interact by texting to circumvent their social problems. At the end of their date Lucy wants to kiss Raj, but gets shy before doing so. Raj is impressed, counting it as foreplay.

Sheldon is tricked into tidying Howard and Bernadette's closet during their dinner party. He finds and reads a letter to Howard on his 18th birthday from his long-lost father. Howard destroys the letter without reading it and otherwise acts strangely. The others trick Sheldon into revealing the letter's content. When Howard finds out everyone knows but him, he storms out of Leonard's and Penny's dinner party. Everyone else heads to Bernadette and Howard's apartment where Sheldon invokes quantum superposition to tell Howard what was in the letter without him actually knowing; each person devises a version of the letter's content, but only one is actually true. Raj says his father sent him a birthday card; Sheldon mentions a map to One-Eyed Willy's lost pirate treasure (this is actually the plot for The Goonies); Amy says his father secretly attended his son's high school graduation and was so proud he cried; Penny says his father's 'other life' caught up with him so he left his family for their safety; Leonard says his father wrote of the importance of family, and that Howard should never abandon his family as he did; Bernadette describes a photo of Howard's father holding him as a baby with the words 'Howard, my son, my greatest gift'. Howard is pleased, wishing all versions were true, and returns to Leonard and Penny's dinner party with everyone else.

After Professor Tupperman's death, Sheldon, Leonard, Raj and Kripke fight for his tenured position and try to impress Janine Davis, Caltech's HR administrator and head of the tenure committee. Leonard and Kripke exercise with her at the gym to talk to her, but Leonard suffers an asthma attack. Raj sends her a 90-minute video autobiography. Sheldon gives her a DVD of the TVminiseriesRoots to make up for his racist comments in The Egg Salad Equivalency but when she doesn't appreciate it, he offends her by asking 'you are black, right?'. Sheldon, Leonard and Raj attend Tupperman's memorial service, Sheldon and Leonard taking Amy and Penny to impress the tenure committee. On their encounter before the memorial service they lash out at each other, even Amy and Penny joining in. The fight stops only when Leonard realizes he would rather lose the tenured post than lose his friends. The five decide to leave, but stay after observing Kripke flatter Mrs. Davis. Sheldon, Leonard and Raj are eventually shortlisted for the tenured position purely on the basis of their accomplishments. Sheldon thanks Mrs. Davis, but offends her yet again by offering her a supposed 'traditional black handshake'.

Sheldon is upset when the SyFy television series Alphas is cancelled on a cliffhanger, and he unsuccessfully calls the SyFy network to get it back on air. Amy decides to teach him to overcome his 'closure' obsession: she forcefully stops him finishing various tasks just before the end. He hides his fury and pretends to be cured, but once Amy leaves, he completes each task she interrupted. Meanwhile Leonard, hoping to find one common interest with Penny, asks her to watch Buffy The Vampire Slayer with him. She pretends to enjoy it to avoid hurting his feelings. Penny reveals to Bernadette that, unlike Leonard, she has no passions, but hopes to change this. During dinner with Leonard, she realizes she is passionate about him and his friends, even Sheldon. Elsewhere, Raj is upset that Lucy's blog post about their date describes him as 'a little feminine'. Howard confirms Raj is effeminate, but says this could be to his advantage with Lucy. Raj rejects his advice: when he cooks at home on a date with Lucy he tries to be more masculine, but just creeps her out. Just as she is about to walk out, he explains he read her blog. She says he is feminine in a 'good way', being sweet, thoughtful, with a 'skin like caramel'.

Sheldon and Leonard find out Dr. Arthur Jefferies aka Professor Proton, who hosted a children's science show they loved as kids, does children's parties. He accepts an invitation to perform in their apartment. He finds it odd to do a children's show for physicists but enjoys performing for Penny, liking her, though he wants to leave when her ignorance of science makes him wonder whatever she and Leonard talk about. He admits disillusion about his TV persona, as other scientists never took him seriously despite his CornellPhD. He is however encouraged to hear Sheldon and Leonard became physicists because of him. He is taken to hospital with a sudden pacemaker problem, and asks Sheldon to represent him at a Korean child's birthday party the next day as he feels too unwell. Sheldon, flattered, now regards Professor Proton as his 'father'. Meanwhile, Raj has Howard and Bernadette care for his Yorkshire Terrier Cinnamon while he is at the telescope lab for the weekend, but they lose Cinnamon in the park. Someone else finds her and contacts Raj. He lambastes them for losing her, but on hearing Cinnamon was found hours earlier, Bernadette makes Raj feel guilty for letting them worry so long.

The women head to Las Vegas for the weekend and Lucy is busy, so the men play Dungeons and Dragons with Howard as a new dungeon master. When Lucy texts Raj that she is free, he kills his own character to leave the game, and joins her for a date, where she admits she is trying to force herself to do things that scare her. The date goes well until he tries to force Lucy to reject her crab cakes. She heads for the washroom and climbs out of the window, but is trapped behind a chain link fence and calls Raj for help. He confronts her for always walking out of their dates but says he really likes her for having even more emotional problems than he does. They kiss through the fence. Meanwhile, at Leonard and Sheldon's apartment, the men's game is interrupted by the women, who could not board their Vegas flight as Amy assaulted a TSA officer who 'groped' her. They join the game. All is fine until Howard asks the characters of Sheldon and Amy to have sex, upsetting Amy, who feels the others are mocking her non-sexual relationship with Sheldon. She locks herself in Sheldon's room. He joins Amy to console her, explaining that he finds their relationship 'intimate' despite not having sex. He has also not ruled out having sex with her one day. They then simulate a sex scene with their game characters.

Stephen Hawking plans a North Sea expedition to find the hydrodynamic equivalent of Unruh radiation. Howard proposes Leonard for the team, though he is reluctant to leave Penny for four months. She acquiesces, whereas Sheldon, jealous of Leonard's career move and afraid of extended solitude, vainly tries to dissuade him. On Penny's advice, Sheldon overcomes his jealousy, later toasting Leonard supportively at his bon voyage party. Meanwhile the men want to meet Lucy, who hates meeting new people, so Raj suggests she first meet just one of them. The honor falls to Amy, the newest of the group. Amy handles Lucy well, but when Raj demands to know the status of their relationship, Lucy escapes to the bathroom. Later, Lucy reluctantly agrees to go to Leonard's party, but instead texts Raj there to break up with him, reducing him to tears. Later, after driving Leonard to the airport, Penny visits Raj to console him. When he says he is unlovable, Penny says the alcohol is talking - yet Raj has been abstinent since Lucy broke up with him. Both are amazed and happy to realize Raj has finally overcome his selective mutism. The episode ends with Raj annoying the women by talking non-stop about Lucy.