The Big Bang Theory

During their honeymoon in New York, Sheldon and Amy encounter difficulties as they adjust to each other's habits. At the same time, Penny and Leonard find themselves uncomfortably reflecting the behavior of Amy's domineering parents. Raj, in a moment of insensitivity, upsets prominent physicist Neil deGrasse Tyson, leading to a public discussion on Twitter.

In one storyline, Sheldon and Amy become obsessed with figuring out the identity of the "perfect gift" that Leonard and Penny gave them for their wedding. In another storyline, Raj expresses a desire to settle down and asks his father to arrange a traditional marriage for him.

The Wolowitz family experiences new dynamics when Stuart brings his new girlfriend to meet his parents. At the same time, Penny and Leonard explore the possibility of starting a family, and Raj considers the idea of an arranged marriage.

Leonard becomes curious about why Sheldon has never mentioned his childhood best friend and decides to look into it on his own. At the same time, Bernadette and Penny take Raj's fiancée to dinner in an attempt to learn more about her.

Sheldon goes to great lengths to ensure Amy's availability for their research on super-asymmetry, inadvertently putting her career at risk. At the same time, Raj opposes Howard's effort to co-host a planetarium show with him.

Sheldon becomes upset when Howard dresses as him for Halloween and takes revenge at Leonard and Penny's party. Meanwhile, Leonard is surprised to learn that Penny cannot recall their first kiss.

Leonard finds himself in a difficult position when he is entrusted with distributing additional grant funds. At the same time, Bernadette uses the backyard playhouse as a way to escape from Howard and their children.

Sheldon tries to connect with Amy's father, but when Howard distracts Mr. Fowler with magic, Sheldon ends up interacting with Mrs. Fowler instead. At the same time, Raj and Anu take their relationship to a new level.

Sheldon and Amy are surprised to learn, through a Russian academic paper, that their scientific theory of Super Asymmetry has already been proposed and subsequently disproven. Meanwhile, Bernadette, eager to surpass Howard, recruits Stuart's girlfriend to assist her in mastering a competitive video game.

Sheldon and Amy are left disheartened when their scientific theory is disproven, until Sheldon discovers a VHS tape from his childhood that reignites his determination. At the same time, Bernadette assumes the role of a competitive pageant mother, aggressively coaching Howard for an audition at the Magic Castle.

Penny and Leonard organize a paintball game, which descends into chaos after Sheldon becomes jealous of Amy's attention. At the same time, Raj discovers Anu with her ex-boyfriend, and Stuart becomes anxious when Denise suggests moving in together.

Penny runs into her ex-boyfriend Zack, who invites her and Leonard to dinner with his new wife. After the meal, Zack and his wife make an unexpected offer to Leonard, which causes Penny to feel upset. At the same time, Raj attempts to reconnect with his ex-fiancée, Anu.

Sheldon and Amy are overjoyed when their super asymmetry theory is confirmed by two physicists, but their celebration is short-lived as the scientists try to omit Amy from the Nobel nomination. At the same time, Bernadette receives approval for one of her drugs at work and recruits a reluctant Penny to head the sales team.

Sheldon agrees to help Bernadette and Howard with paperwork but becomes distressed upon discovering they are engaged in an illegal activity. At the same time, Leonard feels excluded when his friends do not involve him in a science-related project.

Penny tries to break Leonard's commitment to an abstention agreement by attempting to seduce him, with the goal of sabotaging her ex-boyfriend Zack and his wife Marissa. At the same time, Wolowitz, Bernadette, and others transform Koothrappali's canceled bachelor party into a romantic trip for the couple.

The gang discovers that Wil Wheaton is hosting a celebrity Dungeons & Dragons game featuring William Shatner, Joe Manganiello, Kareem Abdul-Jabbar, and Kevin Smith. With only one seat remaining, the group must maneuver through a cutthroat competition where deception and betrayal emerge as essential tactics in the race to claim the final spot.

Penny and Bernadette go to San Diego for a pharmaceutical sales conference, leaving Howard responsible for looking after the children. At the same time, Sheldon finds a book about child experimentation, which leads him and the others, including Amy, to spend the day participating in related activities.

Pemberton and Campbell earn public favor during a promotional tour, prompting Sheldon and Amy to seek support from Nobel Prize winners Kip Thorne, George Smoot, and Frances Arnold. Meanwhile, Halley's fear of the dark leads to both challenges and unexpected situations at the Wolowitz household.

Amy struggles with the pressure and expectations that come with winning a Nobel Prize, which ultimately leads to an emotional breakdown. At the same time, Howard and Raj try to relive past memories after Howard buys a scooter similar to one he had in the past.

Raj begins to worry about his standing within the scientific community after releasing a contentious paper that proposes the potential existence of extraterrestrial life, while Leonard aims to assume a leadership position in a research initiative focused on plasma physics.

Sheldon and Amy discuss whether to reveal Dr. Pemberton's misconduct after Kripke presents evidence of academic fraud. Meanwhile, Howard learns that several women from his past had romantic feelings for him.

At first, Leonard is happy to see Beverly and responds warmly to her kindness, but his mood changes when he learns her real reason for coming. In the meantime, Denise and Stuart stay at the Wolowitz house much longer than anticipated.

Sheldon and Amy await an important announcement, while Penny and Leonard share a significant update. Howard and Bernadette face the anxiety of leaving their children for the first time, and Raj develops a new friendship as the group moves forward into an uncertain future.

Johnny Galecki and Kaley Cuoco look back on the past 12 years, sharing behind-the-scenes stories and personal memories from the show.