The Big Bang Theory (season 8)

Forty-five days after leaving Pasadena, Sheldon finds himself in a train station in Kingman, Arizona with all of his possessions (and his pants) stolen. He calls Leonard to pick him up, and he brings Amy with him. Heading home, Sheldon says that he never left any of the train stations during his journey. Amy is hurt he left without telling her, and that he called Leonard for help. Sheldon is not happy that she is there, and says he did not call her because he was too embarrassed to admit that he could not make it on his own; Amy accepts that he is not perfect. Sheldon thinks his trip has left him ready to deal with change, but he immediately walks out of the apartment when he sees Penny's new haircut.

Bernadette gets Penny a job interview with her pharmaceutical company as a salesperson, though Penny is very nervous about it. She does horribly in the interview, but gets the job anyway, after bonding with the interviewer over their shared fear of Bernadette.

Howard and Raj find Stuart still living with Howard's mother even though she had recovered, which is very unsettling to Howard.

Recurring characters: Kevin Sussman as Stuart Bloom and Carol Ann Susi as Mrs. Wolowitz
Guest star: Stephen Root as Dan

Sheldon is allowed to study what he wants in exchange for becoming a junior professor and teaching a class; he is not happy, and nobody signs up for his class because of his reputation. Howard decides to take the class to work on a doctorate, but Sheldon focuses on areas of physics that Howard does not understand to humiliate him. Howard gets him back by being a horrible student leading to an incident where he shoots a spitball into Sheldon's mouth, causing him to be reported to Human Resources. After dropping the class, Howard asks Sheldon engineering questions which Sheldon answers. The men eventually heal by celebrating their own genius, and asking each other questions.

Meanwhile, Bernadette feels Penny should start studying for her pharmaceutical job, but Penny wants to wait, which leads to tension. Amy loves being in the middle, pretending to agree with both of them. Now she can spend time with each one alone, and increase her bond of friendship by trash talking about the other woman and feeling immensely popular. Her good times are short-lived when Bernadette and Penny apologize to each other, and Amy ends up eavesdropping on her friends to see if they are getting along.

Recurring character: Regina King as Janine Davis

Howard is asked to throw out the first pitch at a baseball game for the LA Angels of Anaheim, as an astronaut, to celebrate Space Day. Despite practicing, he cannot reach home plate. At the game Howard decides to use a prototype of the Mars rover to deliver the ball, but the Rover moves so slowly across the grass to deliver the ball that Howard is booed by the crowd and his friends in the stands.

Earlier Sheldon and Amy are joined by Penny and Leonard on a double date at a pub, and are baffled when Sheldon says the Shamy relationship is the stronger of the two, because they scored an 8.2 out of 10 on a scientific test used to measure a couple's compatibility. Leonard wants to take the test, but Penny refuses, worried that she and Leonard have nothing in common even though they are engaged. Leonard admits he shares this fear, but says it only strengthens his resolve that they can face it together. Penny is overwhelmed by Leonard's commitment, while Amy wishes Sheldon would say romantic things like that to her. Sheldon tells her that she should trust him that she is already happy because of their test score.

Recurring character: Michael Massimino as himself

Leonard and Penny finally meet Raj's girlfriend Emily, but Penny feels that Emily does not like her. Emily agrees to let Penny practice a pharmaceutical sales pitch on her; however, Emily ignores her pitch. Emily admits she is unhappy that Penny previously hooked-up with Raj. Raj brings the two of them together to talk and Emily apologizes for being rude; however, after the meeting both women part and it is clear that they are still very uncomfortable with each other.

Since Stuart did not get enough insurance money to reopen his comic book store, the men decide to invest in it as part owners. Penny wonders why Leonard wants to discuss finances, while Amy and Bernadette reluctantly accept the investment. Howard's mother has already given the money to Stuart and is calling him by Howard's old pet name Bubula upsetting Howard.

Finally, the men are disappointed that they are not getting a nice comfortable homey place to sit and read comic books, though that is what they are doing in Leonard and Sheldon's apartment.

Recurring characters: Kevin Sussman as Stuart Bloom, Laura Spencer as Emily Sweeney
Title reference: Emily's reaction to Raj and Penny having "slept together" in the season 4 finale.

Sheldon claims the men have not invented anything significant recently because they had all been distracted by their girlfriends, so they plan a weekend of brainstorming. The girls use the free time to go to Las Vegas.

Reviewing their old brainstorming sessions they find only ideas that involve robot girlfriends. Next they work on the hover board from Back to the Future Part II, but keep getting distracted much to Leonard's frustration. Later at Leonard's lab they have further distractions from the internet and end up back at home watching Ghostbusters along with Leonard.

Meanwhile in Vegas, the girls are about to go out when Penny is given some home work by her boss. Bernadette and Amy leave and get drunk. When they return to their room, they find Penny still studying, but take her with them to a strip club, where Amy and Bernadette have fun while Penny keeps studying. The next morning a relaxed Penny heads to the pool and gets her revenge for last night by blinding Bernadette and Amy with the sun from the window while they both deal with extremely terrible hangovers.

Title reference: The weakening of the men's focus on their work due to their other halves.

After Penny gets a company car she sells the one that Leonard gave her in "The Friendship Turbulence", and gives him the money, it bothers Leonard and leads to a conflict between the two. They later share a dinner with Howard and Bernadette to seek their counsel on marriage and finances, but this in turn leads to an argument between Bernadette and Howard over money. Leonard and Penny decide to use it as an example of what not to do in their marriage and finish having sex on the money. Bernadette and Howard eventually make up as well.

Raj and Sheldon see a chance to study dark matter by participating in experiments conducted in a salt mine. To test themselves, they crawl into a hot, sweaty steam pipe tunnel in the university basement with Amy waiting above ground. Sheldon fights several phobias including fear of enclosed places. He also reveals his fear that his new research will fail him like string theory did. Raj consoles him by relating his own fear when he first left India. When some rats show up Sheldon abandons Raj, who later excoriates Sheldon for doing so. Their simulation lasts eleven minutes.

Sheldon meets the middle-aged Dr. Lorvis who tracked down a flirty pharmaceutical sales rep, Penny. Leonard explains to him that Penny is his fiancée, so he walks away looking sad. Sheldon invites him inside for a hot beverage. He is a celebrity urinary specialist with a huge memorabilia collection which he invites the men to see. After Sheldon teases that the Penny-Leonard relationship is doomed to fail, Dr. Lorvis locks them in his basement to go after Penny again. He falls for Amy and then Bernadette. Penny explains to him that he is acting creepy, and cannot chase every woman that is nice to him. The girls march him back to let the men out, who are too busy playing Donkey Kong to notice.

Earlier Bernadette tells the girls that she has been picked as one of the fifty most beautiful scientists for an article in a magazine. The magazine cancels the article because Amy wrote an email of complaint about the article since they would not have written about handsome male scientists and are objectifying women. Bernadette claims Amy is jealous because she cannot express her sexuality. Bernadette returns to apologize when she gets hit on by Dr. Lorvis.

Guest star: Billy Bob Thornton as Dr. Oliver Lorvis

After finding Penny's old prom dress the girls decide to have a new prom on the roof. Sheldon is worried about the post-prom mating activities that he feels Amy will expect and has a panic attack after he sees how pretty Amy is. Amy reassures him he is under no pressure, but she does hope they will have intimacy one day. She also wants to tell Sheldon something, even if he can't say it back. Sheldon surprises her by saying he loves her. Amy is shocked, then starts having a panic attack of her own.

Howard is not happy since he figures Stuart will bring his mother. Stuart embarrasses him by bringing Howard's second-cousin Jeanie, the girl Howard lost his virginity to. Howard attacks Stuart in the limo for having relationships with his family members. A jealous call from Debbie causes Stuart to abandon Jeanie at the prom. Emily reveals she loves the darker versions of fairy tales, disturbing Bernadette.

Leonard and Penny dance together romantically though no music is playing. They admit that they probably wouldn't have approached each other to dance if they had met at their proms, but are happy together now.

Note: This is Carol Ann Susi's last episode as Mrs. Wolowitz before her death on November 11, 2014.

Recurring characters: Kevin Sussman as Stuart Bloom, Carol Ann Susi as Mrs. Wolowitz, Laura Spencer as Emily Sweeney
Guest star: Kara Luiz as Jeanie

Leonard announces that he needs surgery in one week because he has a deviated septum. Sheldon is appalled and doesn't want Leonard to have the surgery due to the risks. After Sheldon describes everything that could possibly go wrong with Leonard’s surgery, Leonard tells Sheldon he’ll reconsider it. Leonard then secretly goes to the hospital with Penny after a last-minute earlier appointment comes up and doesn't tell Sheldon, though Amy eventually spills the beans. Sheldon shows up in the waiting room and the hospital experiences a mild earthquake. Sheldon worries about Leonard and runs toward the operating room, hits the glass door and knocks himself to the ground. The next day both Leonard and Sheldon are home with their noses bandaged. Leonard teases that Sheldon only did what he did because he really loves him. Later, Sheldon receives morbid urns he ordered for him and Leonard. However, he is unable to return them because he had gotten them engraved with the morbid messages.

Raj is fretting over finding a gift for his parent’s 40th wedding anniversary until he learns that his parents are getting divorced and his father has moved out. Raj says little things caused them to resent each other over the years. Bernadette and Howard cheer him up, but Bernadette fears the same thing could happen to her marriage. Howard and Bernadette try to say positive things about each other, but it turns into sarcastic bickering.

Note: In lieu of the traditional vanity card at the end of the show, a picture of Carol Ann Susi (the voice of Mrs. Wolowitz, who passed away during the week) was shown in remembrance.

Leonard, Raj and Howard clean out the office of the deceased Professor Roger Abbot and find a bottle of champagne meant to be opened when he made his first great scientific discovery. They take a journal with a bunch of numbers to his coworker Professor Sharpe, who reveals it is just a food diary of how many calories Professor Abbot ate. Abbot believed that he would live forever if he controlled his calorie intake. The men realize not every scientist can make great discoveries, and resolve to drink that champagne in Roger's honor if one of them ever discovers something.

Sheldon prepares his final episode of "Fun with Flags" and reviews highlights of the series including Amy dressing up as a kangaroo, Sheldon dressing up as Betsy Ross, and playing "Fwag, Not a Fwag" with Barry Kripke. LeVar Burton is Sheldon's final guest. No one comments on the series ending until one person posts that he will miss it, causing Sheldon to revive the series and open Roger's champagne in front of Leonard.

Penny and Bernadette attend a banquet for their pharmaceutical company. Their boss Dan is afraid of Bernadette. Penny makes Bernadette realize she has been verbally bullying others. Bernadette goes to apologize to Dan and starts crying when she hears how she's offended her coworkers. Dan feels bad and starts giving Bernadette what she wants again.

Recurring character: John Ross Bowie as Barry Kripke
Guest stars: LeVar Burton as himself, Stephen Root as Dan and Paul Wilson as Professor Sharpe

Raj will be unable to host Christmas dinner as his father is coming to town and is depressed about his divorce. Amy hosts a Victorian era Christmas dinner instead. Her traditional party games bore everyone.

Sheldon and Amy have agreed not to exchange gifts, but Sheldon decides to get her one anyway as revenge for the dinner and kissing him in public under the mistletoe. Bernadette takes him to the mall where he gets his picture taken with Santa and a frame which includes a personalized Christmas message to Amy. To his surprise she loves it and gives him a box of Christmas cookies made from his grandmother's recipe, making them both happy and makes Sheldon wonder about the spirit of giving presents at Christmas time.

Meanwhile, Leonard and Howard are working together in a clean lab when a pigeon flies in. They are unable to get the bird out even with Raj’s help. Howard is devastated when he accidentally injures the pigeon with a blast from a fire extinguisher. Leonard tells him how to revive it; however, a crow flies in. Howard and Leonard agree to take the blame for ruining the lab together until Penny convinces them to erase their names off the sign-up sheet for the lab and leave.

Recurring characters: Brian George as Dr. V.M. Koothrappali

Sheldon and Leonard are excited to play a board game until Amy and Penny say they are tired of doing what the guys want. Sheldon suggests they go clothes shopping since the girls want to do something the guys hate. While waiting, Sheldon mentions that he knows how to compromise because of all he does for Leonard, including still letting Leonard chauffeur him around town, although Amy is teaching him how to drive. Leonard angrily explains how difficult Sheldon can be and that he is not living with Penny, despite their engagement, only for Sheldon's sake. Sheldon apologizes and they both cry over them living apart soon. They decide that Leonard should move out gradually, and Sheldon agrees to let him start spend one night a week at Penny's and let him whistle when he isn't home. Leonard spends the night at Penny's, with Sheldon sleeping on her couch.

Meanwhile, Raj was part of a team that launched the New Horizons Space probe nine years ago, which is going to be activated. A stressed Raj spends the day with Howard and Bernadette and decides to take Howard to a Hindu temple. Howard is surprised Raj leans on religion as a scientist, but agrees to support him when they get to the parking lot. Raj verbally berates a man who dinged his car door, only to calm down when he hears his space probe is fine.

Sheldon has a problem in his dark matter Proton decay research. After Penny says doing a fitness routine she hates motivates her, Sheldon seeks to do the same with his anxiety level while he works. The guys enjoy irritating Sheldon when he asks them to do so, while he annoys the women when he tries to listen to their mindless girl talk. Sheldon becomes exhausted and hallucinates among other things. A frustrated Amy throws him out of her apartment when he focuses on his research and anxiety during their date night. On the bus home he hallucinates a man is really a mix of an Armadillo and Isaac Newton. Leonard and Penny are able to get an exhausted Sheldon to sleep after singing Soft Kitty to him. Sheldon is able to continue his research afterwards.

Meanwhile, Howard has invented a game 'Emily or Cinnamon' where the rest of the friends try and guess whether an embarrassing quote from Raj was said to his girlfriend or his dog. Raj is annoyed, but Emily is okay with it, thinking it is sexy that Raj is sensitive. She kisses Raj and is turned off by the dog hair in his mouth.

Recurring characters: Laura Spencer as Emily Sweeney, Ed Lieberman as Man

Leonard has a revelation about Superfluid vacuum and presents his theory to Sheldon who approves. Sheldon writes a paper on their work and they post an online paper together. It is well received except for one troll who makes disparaging comments. Sheldon challenges this person, but panics when he tries to Video call him. Leonard and Sheldon decide to stand up for themselves and are stunned when their harasser is revealed as Professor Stephen Hawking who commented negatively out of boredom and actually liked their paper.

Meanwhile at Penny's apartment the girls spend the night embarrassing each other. They first watch the terrible gorilla movie that was Penny's last acting job. Then Penny finds some video footage of a younger Bernadette in a beauty pageant. And finally Bernadette reveals Amy's romantic Fanfiction of Little House on the Prairie theme about her and Sheldon. The women become invested in the story. Leonard also enjoys Penny reading the fan fiction to him, but stops before a sex scene.

Guest stars: Jim Meskimen doing two different voice characters, Stephen Hawking as himself

Barry Kripke stops by to thank Amy for helping him with her ideas on string theory, which bothers Sheldon because she never helped him out when he was working on it. He complains to Penny who tells him to "let it go". Instead, Sheldon reveals that Amy was secretly performing experiments on Penny and Leonard and comparing the results with those of a chimpanzee, infuriating Penny.

Leonard and Raj run into Nathan Fillion at a deli, but he denies he is an actor so he can eat in peace. Later, he admits who he is and offers to take a picture with them. Raj asks so many questions to verify Fillion's identity that he looks annoyed in the photo.

Stuart has opened his new comic book store, which impresses everyone except Howard who finds him using the den furniture that his mother had given him. Howard gets a call from Florida where his mother is visiting, and receives news that she died in her sleep. Everyone, including Sheldon, goes to comfort Howard. After he and Bernadette leave for Florida, the rest of the gang remember and toast the passing of Mrs. Wolowitz, calling her "everyone's mother".

Recurring characters: John Ross Bowie as Barry Kripke, Kevin Sussman as Stuart Bloom
Guest stars: Nathan Fillion as himself, Angela Relucio as Hostess

Amy has read about an experiment claiming two people can fall in love by asking each other a set of personal questions and staring into each others eyes for four minutes. Sheldon and Penny try it in her apartment. Penny reveals she wishes she was as smart as her friends and Sheldon wishes he had Penny's ability to understand social interaction and letting Penny know the secret that his birthday is that day. They do not fall in love but happily reflect on their friendship. Sheldon is startled when his friends throw him a surprise party when he returns home.

Raj, Emily, Leonard and Amy try a bit of interactive theater where participants have to solve puzzles to get out of a room. The four are disappointed after their scientific skills solve everything in six minutes.

Meanwhile, Howard and Bernadette are at the airport having returned from his mother's funeral in Florida and are outraged the airline has lost her ashes. Howard feels guilty he unknowingly rejected his last chance to talk to his mother by not driving her to her flight. He is relieved when her ashes are found but Bernadette worries he will put them in their bedroom.

Recurring character: Laura Spencer as Emily Sweeney

Guest stars: Max Adler as The Zombie

Sheldon and Amy decide to progress their relationship by buying a pet turtle. However, Sheldon changes his mind after it bites him and Amy is hurt when she learns Sheldon has applied to colonize the planet Mars without consulting her. Sheldon doesn't understand why she can't support the opportunity, however Amy makes him realize she wants them to plan their future together. They agree to make another application as a couple and are both amused that if they had children there they would technically be Martians.

Leonard has bought some body paint and a canvas for himself and Penny to have sex on. They are disappointed with the initial results but push themselves into making something they like. They decide to give the canvas to Sheldon by telling him William Shatner painted it.

Meanwhile, Emily leaves Raj alone in her apartment and Raj breaks a drawer while snooping. Raj fails to fix it with Howard and Bernadette listening via video call. Emily is angry, but soon forgives him and gets her revenge by scaring Raj into thinking there is something morbid in her closet.

Note: In lieu of the traditional vanity card at the end of the show, a picture of Leonard Nimoy, who passed away the previous week, was shown in remembrance.

Recurring character: Laura Spencer as Emily Sweeney

Scientific American praises the paper Leonard and Sheldon wrote together, but does not mention Leonard's name. Sheldon fails to comfort Leonard over the omission, while Penny tries to cheer up Leonard by doing some online shopping for him.

Meanwhile, Howard, Bernadette and Raj arrive at Howard's mother's home to remove some of her belongings, only to be told by Stuart the power is out. A distraught Howard realizes the last food his mother ever cooked will defrost in the freezer and be ruined. He decides to invite his friends over to eat it all, so it will be like his mother is feeding everybody one last time. At the dinner, Sheldon and Leonard argue about whether an idea's inspiration or execution is more important. Bernadette takes Sheldon and Leonard to another room and scolds them for their bickering. Howard remarks that Bernadette's yelling sounds similar to his mother's, though the others claim to not hear it. Finally, everyone is over-stuffed from eating and lazing around the house. The group expresses mild excitement upon hearing that an online publication has mentioned Leonard's name in connection to the paper, but become much more enthusiastic when Bernadette finds more Tums.

Recurring character: Kevin Sussman as Stuart Bloom

Sheldon and Leonard are headed to UC Berkeley to give a lecture on the paper they wrote together. They decide to drive by Skywalker Ranch and Sheldon wants to go inside, hoping to meet George Lucas. They get past the front gate, but Leonard tells the security guard the truth. Sheldon decides to make a run for it and is hit with a Taser. They are let off with a warning and are forbidden to return. At home Leonard is initially angry, but admits it was a fun adventure and he enjoyed seeing Sheldon get electrocuted.

Meanwhile, the rest of the gang are cleaning out Mrs. Wolowiz's house for a garage sale. A dispute occurs over Howard's Doctor Who's TARDIS. They agree to decide its fate via a Ping pong match with Penny playing for Bernadette and Raj for Howard. Penny starts losing so Bernadette says Raj has to take it can buy it and he starts playing for her with Amy playing for Howard. Amy is about to win until Bernadette says she could have the TARDIS's doors to trick Sheldon into going inside her bedroom. Amy does so, but is disappointed when Sheldon runs into her bedroom dressed as the Fourth Doctor and then leaves.

Sheldon is depressed because he was left out of a group attending a symposium at the home of Richard Feynman. On date night he mentions to Amy how his siblings left him out of building a blanket fort as kids. They decide to build their own in the living room and Sheldon has so much fun he agrees to let Amy spend her first night with him in a platonic sleepover. Amy had left a pre-positioned sleepover kit in the apartment just in case.

Wil Wheaton has Penny on his podcast to talk about the terrible movie they worked on together, "Serial Ape-ist 2". Kevin Smith calls to offer her an audition for Clerks III. Leonard, who is not thrilled with her risking her good pharmaceutical job, is stunned when he learns she makes twice the money he does and is being more mature than him. Penny says she will do something immature by going to the audition, tricking Leonard into supporting her possibly acting again.

Howard now owns his mother's house after his father Sam signed it away with no contact. While discussing future plans with Raj and Bernadette, Howard is shocked when he is visited by a half-brother, Josh. Howard wants him to leave, but they bond over Howard being an astronaut and his lustful past with a robotic arm.

Recurring character: Wil Wheaton as himself
Guest stars: Matt Bennett as Josh, Kevin Smith Voice-over as himself

Raj is working on a proposal for NASA to design a message from Earth and its delivery system to hopefully be found by an Alien life form. He asks the guys for advice and Sheldon and Howard try to take control, so Raj invites only Leonard to work with him. The two realize Sheldon and Howard's ideas were good and ask them to work with them after all. The guys talk about times where they have individually felt excluded from fun group activities while working together on the message. Their message is found by aliens who think Sheldon looks delicious.

Penny is unsure whether she should risk her new career for a chance at acting again and goes to Sheldon for advice. At first Sheldon will not tell her what to do because people think he is too controlling. Penny uses his love of trains in an analogy to get him to say she should go to the audition, but not decide on any major career change yet. Penny's audition goes terribly while she also remembers she hates the petty environment around other actresses. Penny thanks Bernadette for getting her the good pharmaceutical job and takes her (and Amy) on a special dinner after Bernadette's prodding.

Guest stars: Sara Erikson as Gwen and Kelli Goss as Chelsea.

Leonard has been asked to give the graduation speech at his old high school in New Jersey and is excited to bring Penny with him; however their flight is cancelled due to bad weather. Penny arranges with the school to broadcast Leonard's speech over Skype and buys him a "sexy graduate" costume for a graduation cap and gown. Leonard's speech starts out boring so he changes it as he reflects on his own high school life. He explains to the smart and forgotten kids that after they graduate the world will find them far more interesting than the popular students.

Raj has bought a quadcopter, but is unable to get it to work so he brings it to Howard and Sheldon. Raj's father is outraged at the cost of it so he cuts off Raj's allowance; however, Raj is able to leverage his parent's divorce as a way to get them both to separately send him more money. Howard tears the helicopter apart, but is unable to get it to work. The guys begrudgingly call tech support like Bernadette suggested. While on the phone the helicopter activates itself after receiving a random signal and flies wildly around the apartment terrorizing everyone.

Recurring characters: Brian George as Dr. V.M. Koothrappali, Alice Amter as Mrs. Koothrappali

Sheldon and Leonard are getting an award for the paper they wrote together and both their mothers are in town to see the ceremony. Both mothers focus on Sheldon making Leonard jealous. He is also irritated when Sheldon tells Penny her engagement ring is really a recycled and recut diamond drill bit. Beverly wonders why Leonard and Penny haven't set a wedding date, while Mary is fine with them waiting. The mothers also get into an argument after Beverly describes Mary's religious beliefs as a superstition. Beverly later reflects with Sheldon that perhaps there are other ways to raise children than she did. The mothers make up and Beverly tries to show affection by hugging Leonard, though it is awkward for both of them.

Meanwhile, Howard and Bernadette have moved into Mrs. Wolowitz's house with Stuart still living there as well. Bernadette is tired of the other two and Raj lying around so she makes them clean the kitchen. Raj points out to Howard that Bernadette acts like his mother. Howard tries to clean the kitchen like an adult but does a poor job. The three men continue cleaning while singing "It's the Hard Knock Life" from the musical Annie.

Recurring characters: Laurie Metcalf as Mary Cooper, Christine Baranski as Beverly Hofstadter and Kevin Sussman as Stuart Bloom