Big Bang Theory

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

Leonard has a revelation about Superfluid helium 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.