The Big Bang Theory's Most Shocking Plot Twists Revealed

The Big Bang Theory's 10 Biggest Plot Twists

Raj and Bernadette cooking on Thanksgiving on TBBT

By Layne Gibbons Published 19 minutes ago Layne is a longtime contributor for ScreenRant and other Valnet brands. Her main focus is entertainment in pop culture, sitcoms, and reality TV. Layne always knew she had a passion for writing and has her Bachelor's in Communications, a Minor in Marketing, and a Master's in Administration. When she isn't writing or editing about the latest in the entertainment industry, she's typically spending time outside with her family. Hiking, walking, or jogging with her kids is where she wants to be. When it comes to shows streaming on Netflix or anything Bravo-related, she's your gal. She loves rewatching reality TV shows like The Real Housewives and Southern Charm, but she adores watching sitcoms like Abbott Elementary, The Big Bang Theory, and Parks and Recreation. Sign in to your ScreenRant account Summary Generate a summary of this story follow Follow followed Followed Like Like Thread Log in Here is a fact-based summary of the story contents: Try something different: Show me the facts Explain it like I’m 5 Give me a lighthearted recap

A well-written plot twist can alter the fates of its characters and change perceptions of a TV series. Few shows have been able to add the curveballs that The Big Bang Theory threw, and as a result, the beloved sitcom spawned 12 seasons, three spinoffs, and countless streaming sessions.

While some TBBT plot twists took a backseat and were small enough to be forgotten (like when Penny shocked everyone by dating Stuart), others created a more interesting and thought-provoking sitcom.

TBBT's plot twists were memorable because they were character-driven as opposed to being written for shock value. The twists and turns were genuine and added value to the characters' backstories.

Leonard And Penny's Parenting Journey

Penny tells Leonard she's pregnant in TBBT

Leonard and Penny's relationship was a journey with ups and downs throughout The Big Bang Theory. Once married, the two were on a stable path and were comfortable in their relationship. However, once the topic of kids was brought up, their smooth sailing came to an end.

Penny once discussed children with Leonard, but after they got married, her desire to have kids came to an end. Penny didn't see herself as a mom and was afraid of the changes that came with being a new parent.

The news was hard for Leonard, but the two remained committed to their relationship. However, a massive plot twist dropped when Penny found out she was pregnant in the series finale. Despite not wanting children and her professional career taking off, she and Leonard leaped.

Leonard Cheated On Penny

Leonard tells Penny he cheated on her on TBBT

Leonard and Penny in the car on TBBT

One of the biggest plot twists on The Big Bang Theory was finding out that Leonard cheated on Penny. After years of Leonard longing for Penny, he eventually made an impression on her heart, and the two got engaged. But as they were on their way to Las Vegas to elope, he dropped a bomb on her: he had cheated on her.

When Leonard was away at sea doing research for Stephen Hawking, he kissed another girl. The only reason he came clean was to start their marriage fresh. Penny assumed he was trying to sabotage their relationship, and the two had to work through his lapse in judgment.

The storyline was a huge twist to their relationship. Many assumed that if anyone was going to cheat on the other, it would be Penny because of her good looks and charming personality.

The admission that it was Leonard who had cheated came from a deeper place. Leonard clearly felt self-conscious in his relationship and needed a boost in confidence by cheating on Penny. It altered the way Penny viewed Leonard and changed the dynamic of their relationship.

Howard's Mom Unexpectedly Died

The gang gathered around Howard's mom's Thanksgiving table in The Big Bang Theory

Howards Moms Last Freezer Meal Episode The Big Bang Theory, All The Big Bang Theory Cast Sitting Around The Table

Howard Wolowitz's mom was an imperative part of his life. Before meeting Bernadette, Howard was the stereotypical mama's boy who lived and died by his mother's opinion. When he grew serious with Bernadette, he spent more time away from his mom, which altered their dynamic.

In season 8, time stopped when Howard got a phone call that his mom had passed away in her sleep. Howard was unprepared for the loss of his mother, and he suffered without closure.

The unexpected death was a plot twist on TBBT, as she was such an important and present figure in Howard's life. The twosome also had some of the funniest scenes in the series. Sadly, this twit came about because the actress who played Debbie, Carol Ann Susi, passed away from cancer in 2014.

Penny Quit Acting For Good

Penny and Bernadette at a sales conference on TBBT

A large part of Penny's ongoing storyline was that she was a struggling actor, and she worked as a waitress at The Cheesecake Factory to pay her bills while trying for her big break.

Penny had a few acting roles here and there, but she never achieved the celebrity status she aspired to. Without acting, Penny didn’t know what else to do with her time.

In season 7, a change in plot occurred when Penny decided to quit waitressing to devote all her attention to acting. However, when that didn't pan out, the plot shifted again when she opted for a more conventional job.

Bernadette worked for a pharmaceutical company, ZanGen, and was able to get Penny a job as a pharmaceutical sales rep. While it was a hard transition at first, Penny stuck with the position and became wildly successful at it, which was a surprise to her friends. By season 12, Penny was making more money than Leonard and was on the road to a successful career.

The Journey Of The Broken Elevator

Leonard and Penny converse in front of the broken elevator in TBBT

A subplot that continued through The Big Bang Theory’s entirety was the broken elevator inside Leonard and Sheldon‘s apartment building. While taking the elevator would have been convenient, walking up three flights of stairs made for comical moments for the characters.

The running gag was that the elevator was always broken after an experiment went wrong. Leonard miscalculated the experiment containing rocket fuel, and the quickest way out of the apartment was to place the object into the elevator. After a small explosion, the elevator stopped working.

The plot twist came in the final season when the elevator door magically opened in the apartment lobby where Sheldon and Leonard were talking. As the doors opened, Penny walked out and joined them.

It was the perfect ending that followed the characters for 12 seasons. It was also one of the best plot twists because the characters had given up on the elevator ever working again.

Howard Found Out He Had A Brother

Howard talking to his brother

Howard had a tough childhood, and the traumas he never worked through followed him into his adult years. After his father left the family at a young age, it was just him and his mom his entire life. Then, when his mom died unexpectedly, Howard found himself. That is, until season 8.

The biggest plot twist in Howard’s life was when a young man showed up at his front door, claiming to be his half-brother named Josh. Josh shared that he and Howard shared the same dad. Howard was hesitant at first and wasn’t sure if he could trust Josh, but the two soon hit it off. Josh only appeared in that episode, but the storyline still had a major impact on HOward.

Penny Was Secretly Married To Zack

Zack at dinner with Penny and Leonard on TBBT

A plot twist that nobody saw coming was Penny’s legal marriage to ex-boyfriend Zack. Although Penny’s dimwitted ex-boyfriend wasn’t a main member of the TBBT friend group, he became a comical side character that pops up over the years.

In “The Thanksgiving Decoupling,” the group is shocked when they find out that Penny married Zack in Vegas years prior. Although Penny thought Vegas weddings were fake, Leonard and co. assured her they were real.

The realization that Penny married Zack was a big shift in her relationship with Leonard. Despite talking about their future together, Penny consistently turned Leonard’s proposals down, so the fact that she agreed to marry Zack so quickly upset Leonard.

Zack later came to dinner to sign the annulment papers so that he and Penny could be legally unwed, but the deeper problems in Penny and Leonard’s relationship surfaced with this plot twist, as Leonard realized that maybe Penny believed in marriage, just not with him.

Sheldon Proposing To Amy

Sheldon Cooper (Jim Parsons) on one knee, looking up, holding a box with a wedding ring in it, and proposing to Amy (Mayim Bialik) in The Big Bang Theory

In season 10 of TBBT, Sheldon and Amy's relationship became even more complicated when it went long-distance, as Amy got a research position at Princeton for the summer while Sheldon remained in California.

Their relationship proved itself strong, but when a former colleague of Sheldon's, Ramona Nowitzki, kissed him at work, it threw a wrench in the mix. Although getting married scared Sheldon, kissing another woman made him realize that he didn't want to be with anyone else. He flew to New Jersey and proposed to Amy.

Sheldon came clean to Amy about the kiss, but instead of being mad at Ramona, she thanked her. If she didn’t kiss Sheldon, it's hard to tell if Sheldon would have ever decided to propose on his own.

Penny And Raj Almost Hooked Up

Raj and Penny in bed together in The Big Bang Theory.

Raj and Penny in The Big Bang Theory

Like many of Leonard’s friends, Raj crushed on Penny before she and Leonard grew serious. She was easy to talk to, beautiful, and a good listener. As someone who wasn’t primarily great with women, it was easy to see why Raj was fond of Penny.

However, once she was single and Leonard moved on, Raj took his chance with Penny after the two had one too many drinks. Raj and Penny were seen waking up naked in bed, side by side. The series implied that the two had sex, which was a major plot twist, considering their friendship with each other and with Leonard.

To make matters worse, Leonard found out about their entanglement after witnessing Raj and Penny leave the bedroom together. While Penny regretted their actions, the twist in the plot continued when Raj came clean about what really happened between them. He shared that the two did not actually sleep together — they only kissed.

The twist within the twist made this storyline a complicated one for the friend group, but they were able to move forward since the two didn't sleep together.

Sheldon's Reason For Knocking Three Times

Sheldon Cooper Big Bang Theory Jim Parsons in spot looking confused

The Big Bang Theory's Sheldon CooperCredit: CBS via MovieStillsDB

Sheldon has plenty of quirks that make him hilariously unique, and one of them quirks is knocking three times (while saying the person’s name on the other side of the door) before entering a closed room.

An explanation was dissected in season 10. Sheldon told Penny that he knocks three times because, as a child, he caught his dad having an affair. Sheldon knocking three times gives people on the other side enough time to stop doing anything they don't want someone to witness.

Knocking three times creates an emotional boundary for Sheldon, where he feels safe as opposed to surprised by what he finds on the other side. This plot twist in The Big Bang Theory made others empathetic towards him. Knocking three times was a coping mechanism, not an annoying idiosyncrasy.

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Like Follow Followed The Big Bang Theory Romance Comedy

6/10 255 8.5/10 Release Date 2007 - 2019-00-00 Network CBS Showrunner Mark Cendrowski Directors Mark Cendrowski

Cast

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Johnny Galecki Leonard Hofstadter
Jim Parsons Sheldon Cooper

Genres Romance, Comedy Seasons 12 Powered by

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Network TV
The Big Bang Theory (Franchise)

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