The Big Bang Theory

In the twelfth season premiere; Sheldon and Amy’s honeymoon runs aground in New York; while Penny and Leonard discover they are uncomfortably similar to Amy’s parents; Meanwhile Raj insults physicist NEIL DEGRASSE TYSON and starts a Twitter war. KATHY BATES and TELLER return as Amy’s parents.

Sheldon and Amy drive themselves crazy trying to figure out what “perfect gift” Leonard and Penny got them for their wedding. Meanwhile; Raj decides he wants to settle down and asks his father to find him an arranged marriage.

Howard and Bernadette’s life gets complicated when Stuart (series regular KEVIN SUSSMAN) starts bringing his new girlfriend home; Meanwhile, Penny and Leonard talk about starting a new family, as Raj explores an arranged marriage.

When Sheldon won’t tell anyone why he’s never mentioned Tam (guest star ROBERT WU), his childhood best friend, Leonard takes matters into his own hands. Also, Bernadette and Penny take out Raj’s fiancée, Anu (guest star RATI GUPTA), for dinner to get all the details on her. JERRY O’CONNELL returns as Sheldon’s brother, George.

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 if it means accidentally sabotaging her career in the process. Meanwhile, Raj doesn’t want Howard to join him in hosting a show at the planetarium. BOB NEWHART returns as Arthur Jeffries.

When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Penny’s Halloween party; Meanwhile, 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. Also, Bernadette turns the backyard playhouse into a hideaway from her husband and kids.

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. Meanwhile, Raj and Anu attempt to get physical.

Sheldon and Amy are devastated to learn from a Russian paper that Super-Asymmetry has already been discovered and disproven. Meanwhile, ultra-competitive Bernadette asks Stuart’s girlfriend, Denise (recurring guest star LAUREN LAPKUS), to teach her how to play the videogame Fortnite.

Sheldon and Amy are still down about their theory being disproven, but a VHS tape from Sheldon’s past inspires him to not give up. Also, Bernadette turns into a pageant mom when she tries to help Howard ace his Magic Castle audition. Special guest stars include Young Sheldon’s IAIN ARMITAGE, LANCE BARBER and MONTANA JORDAN. CHRISTINE BARANSKI returns as Leonard’s mother, Beverly.

Penny and Leonard organize a paintball game that results in mayhem, when Sheldon is jealous of Amy, Raj catches Anu with her ex-boyfriend, and Stuart doesn’t want to move in with Denise.

Penny’s old boyfriend, Zack (recurring guest star BRIAN THOMAS SMITH), and his wife want a baby, but when Zack is infertile, they ask Leonard to help. Meanwhile, Raj attempts to mend things with his ex-fiancée Anu.

When Sheldon and Amy’s Super Asymmetry Theory is proven by two physicists from Chicago, they’re thrilled – until they try to kick Amy off their Nobel Prize nomination! Meanwhile, Bernadette has a big success at work and Penny’s going to be a part of it…whether she wants to or not.

Sheldon is thrilled to help Howard and Bernadette navigate bureaucratic paperwork… until he discovers they are breaking the law. Now, he’ll have to choose between following the rules of staying loyal to his friends. Meanwhile, Leonard is disappointed when his friends exclude him from a scientific project.

Penny tries to seduce an abstaining Leonard to ruin his “donation” for her ex-boyfriend, Zack, and his wife, Marissa (recurring guest star LINDSEY KRAFT). Meanwhile, Howard, Bernadette, Raj and Anu turn Raj’s canceled bachelor party into a “couple’s trip” aboard the “Vomit Comet.” Keith Carradine returns as Penny’s father, Wyatt.

When the gang finds out that Wil Wheaton hosts a celebrity Dungeons & Dragons game involving WILLIAM SHATNER, JOE MANGANIELLO, NBA legend KAREEM ABDUL-JABBAR and director KEVIN SMITH, deception and betrayal are the path to make it to the one open seat.

When Penny and Bernadette got to San Diego for a pharmaceutical sales convention, Howard is left in charge of the kids. But when Sheldon finds a book on experimenting with children, the guys and Amy make a day of it.

When competitors Pemberton and Campbell (guest stars SEAN ASTIN and KAL PENN) charm America on a publicity tour, Sheldon and Amy try to bring Nobel laureates KIP THORNE, GEORGE SMOOT and FRANCES ARNOLD to their side (this episode sets the record for most Nobel laureates appearing in a comedy). Meanwhile, Halley’s fear of the dark leads to both opportunity and conflict for Howard, Bernadette and Stuart.

The concept of what it would mean for women everywhere if Amy were to win a Nobel Prize causes Amy to have a meltdown. Meanwhile, Raj and Howard try to relive the good old days when Howard buys a scooter that resembles the one he had years ago.

While Raj is worried that people won’t take him seriously in his own field after publishing a paper suggesting he may have discovered alien life, Penny encourages Leonard to stand up for himself when he wants to be the principal investigator on a plasma physics study.

When Barry Kripke finds proof that Dr. Pemberton plagiarized his thesis in college, Sheldon and Amy aren’t sure if they should turn him in or not. And Howard is happily surprised to learn that Bernadette wasn’t the only waitress at The Cheesecake Factory who had a crush on him back in the day.

Leonard is pleasantly surprised when his mother, Beverly, comes to visit and she’s genuinely kind toward him – until he finds out the real reason why she’s there; Meanwhile, Denise and Stuart overstay their welcome at the Wolowitz house.

Everything changes as Sheldon and Amy await big news in the first of a two-part series finale.

It’s an end and a beginning on the second of a two-part series finale. Howard and Bernadette leave their kids for the first time; Leonard and Penny try to keep a secret; Sheldon and Amy stick together; and Raj makes a new friend as the gang travels together into an uncharted future.