Sheldon and Leonard try to divvy up their shared belongings, but can’t agree on anything. Also, Koothrappali and Stuart fight to be the most helpful during Bernadette’s final weeks of…

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas.

After Sheldon’s mother and Leonard’s father share an evening together, everyone deals with an awkward morning the next day. Also, Penny’s family arrives for the wedding ceremony, including her anxiety-ridden…

Colonel Williams, an Air Force representative from the Department of Material Command sits down to talk with Wolowitz.

Tensions rise when the boys struggle to complete their government project on time and Sheldon tries an energy drink to stay awake. Also, Penny and Amy go to a “party”…

When Amy’s apartment floods, she proposes a “cohabitation experiment” with Sheldon. Also, Howard and Bernadette are upset when Koothrappali learns the gender of the baby before they do.

Leonard and Penny must separate a quarreling Sheldon and Amy when their cohabitation does not go as planned, and Sheldon threatens to break off their relationship when Amy refuses to…

Penny is surprised to learn she has fans of her performance in “Serial Ape-ist” when she attends Van Nuys Comic Con with Leonard. Also, Amy hosts a Sheldon-style brunch at…

Sheldon and Amy await big news.

When Penny and Bernadette go to San Diego for a pharmaceutical sales convention, Wolowitz is in charge of the kids. Also, Sheldon finds a book on experimenting on kids, and…

When competitors Pemberton and Campbell charm America on a publicity tour, Sheldon and Amy try to bring Nobel laureates Kip Thorne, George Smoot and Frances Arnold to their side. Also,…

The concept of what it would mean for women everywhere if Amy were to win a Nobel Prize causes Amy to have a meltdown. Also, Koothrappali and Wolowitz try to…

Koothrappali is worried people won’t take him seriously in his own field after publishing a paper that suggests he may have discovered alien life. Also, Leonard wants to be the…

When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Penny’s Halloween party. Leonard is shocked that Penny doesn’t remember their first kiss.

Leonard is caught between a rock and a hard place when he’s responsible for distributing extra grant money. Bernadette turns the backyard playhouse into a hideaway from Howard and the…

Sheldon tries to bond with Amy’s father, but when Howard lures Mr. Fowler away with magic tricks, Sheldon has no choice but to bond with Mrs. Fowler. Raj and Anu…

Sheldon and Amy are still down about their theory being disproven, but a VHS tape from Sheldon’s past inspires him not to give up. Bernadette turns into a pageant mom…

Penny and Leonard organize a paintball game that results in mayhem when Sheldon is jealous of Amy. Also, Raj catches Anu with her ex-boyfriend, and Stuart gets cold feet when…

Penny runs into her ex-boyfriend, Zack, who invites her and Leonard to a dinner to meet his newlywed wife. After the dinner the newlywed couple make an odd proposition to…

Sheldon and Amy are thrilled when their super asymmetry theory is proven by two physicists, until they try to kick Amy off the Nobel nomination. Also, Bernadette gets one of…

Sheldon is thrilled to help Bernadette and Wolowitz navigate bureaucratic paperwork, until he discovers they are breaking the law. Also, Leonard is disappointed when his friends exclude him from a…

Penny tries to seduce an abstaining Leonard to ruin his “donation” for her ex-boyfriend, Zack, and his wife, Marissa. Also, Wolowitz, Bernadette, Anu and Koothrappali turn Koothrappali’s canceled bachelor party…

The gang finds out Wil Wheaton hosts a celebrity Dungeons and Dragons game involving William Shatner, Joe Manganiello, Kareem Abdul-Jabbar and Kevin Smith. Deception and betrayal are the path to…

Sheldon and Amy drive themselves crazy trying to figure out what ‘perfect gift’ Leonard and Penny gave them for their wedding. Raj decides he wants to settle down and asks…

The Wolowitzes’ life gets complicated when Stuart starts bringing his new girlfriend home. Also, Penny and Leonard talk about starting a family, while Raj explores an arranged marriage.

When Sheldon learns that his mother won’t attend his wedding unless he invites his brother, Georgie, he and Leonard travel to Texas to end a family feud. Also, the Wolowitz…

When Amy’s parents and Sheldon’s family arrive, everybody is focused to make sure all wedding arrangements go according to plan – everyone except the bride and groom.

When Sheldon won’t tell anyone why he’s never mentioned his childhood best friend, Leonard takes matters into his own hands. Bernadette and Penny take out Raj’s fiancée for dinner to…

Raj and Howard’s feud continues as the gang plan Halley’s first birthday party. Sheldon’s surprise for Amy’s birthday goes awry when they get food poisoning. Also, Leonard gets a Christmas…

When Amy doesn’t have time to work on super-asymmetry, Sheldon goes to great lengths to ensure she’s available to work with him even it if means accidentally sabotaging her career…

Sheldon and Amy try to pick their Best-Man and Maid of Honor by experimenting on the gang.

When Sheldon kicks Amy out to work solo, she and Leonard bond during a series of science experiments. Also, Bert the geologist replaces Wolowitz in the band Footprints on the…

Raj finds himself in the middle of domestic drama when he learns the woman he’s dating, has a very upset husband. Also, when Sheldon rents his old room back for…

Leonard’s book raises questions, and Amy guest stars on the new Professor Proton show.

Leonard jumps through hoops to help secure the perfect wedding venue for Sheldon and Amy. Also, Bernadette and Howard have a hard time deciding who should stay at home with…

Bill Gates visits Penny’s work, and the gang schemes to meet him. Hilarity ensues. Meanwhile, Sheldon is convinced that he’s a target of an April’s Fools prank.

When Leonard learns Sheldon is the president of the tenants association, he decides to run against him. Also, Bernadette encourages Howard and Raj to find the owner of a drone…

A brilliant but reclusive scientist, Doctor Wolcott, invites Sheldon to his cabin in the middle of nowhere, and Leonard, Raj and Howard go along for the trip. Also, Penny and…

Sheldon and Amy’s honeymoon runs aground in New York. Penny and Leonard discover they are uncomfortably similar to Amy’s parents. Raj insults physicist Neil deGrasse Tyson and starts a Twitter…

Sheldon’s comic book store experiences changes when writer Neil Gaiman puts Stuart’s store on the map. Also, friendships are threatened when Raj takes credit for Penny’s astronomical discovery.