A successful gene experimentation leaves Sheldon excited to procreate with Amy, and he pulls out all stops to get her on board. Meanwhile, Koothrappali is reluctant to reveal what the new woman in his life does for a living.

Penny's job offer from a former boyfriend doesn't sit well with Leonard.

Leonard, Sheldon and Wolowitz celebrate the successful completion of their top-secret military project, until an unpleasant surprise leaves their heads spinning. Also, Amy considers an offer of a summer position as a visiting researcher.

On the Season 10 finale, Sheldon's former admirer, Dr. Ramona Nowitzki, turns up while Amy is visiting Princeton, and the gang is extremely concerned.

Season 11 begins with Amy giving Sheldon an answer to his marriage proposal. Meanwhile, Howard and Bernadette struggle with some unexpected news.

Leonard angers the university and the entire physics community when he gives an embarrassing radio interview. Meanwhile, Amy and Bernadette bond over having to hide their success from Sheldon and Howard.

Amy records Sheldon talking in his sleep and tries to convince him that he has a more laid-back side. Meanwhile, Koothrappali and Stuart compete to win the heart of Bernadette's new co-worker.

Wolowitz and Sheldon bond over their relationships with their disappointing fathers when they drive to the desert to shoot off a model rocket. Meanwhile, Leonard's mom finds a new best friend in Penny, much to Leonard's dismay.

Sheldon and Koothrappali confide in Bernadette when they can't handle Amy and Wolowitz working together. Meanwhile, Penny and Leonard learn new tactics on how to deal with Sheldon and they come from an unlikely source.

Sheldon and Bert collaborate on a research project, despite Sheldon's embarrassment. Also, Penny and Bernadette coach Koothrappali on how to navigate his relationship with Ruchi.

Leonard and Wolowitz are furious after they learn Sheldon went to work with the military behind their backs. Also, while Bernadette is on bed rest, she asks Raj to do some digging when she suspects Ruchi is trying to steal her job.

Sheldon and Wolowitz plan birthday celebrations for Amy and Halley, respectively. Also, Leonard receives a Christmas letter from his brother that causes him to spiral out about his own lack of accomplishments.

Sheldon tries to teach the guys a lesson after they cut him out of a potentially valuable Bitcoin investment. Also, a seven-year-old video reveals a secret about Leonard and Penny's relationship.

The men compete in the university's lighthearted physics bowl, but Sheldon's much-too-serious attitude forces them to replace him with his nemesis, Leslie Winkle (Sara Gilbert).

Wolowitz is embarrassed when a secret of his is revealed; and Sheldon and Raj battle at work.

There's trouble in paradise when Amy discovers Sheldon signed up for a one-way mission to colonize Mars, and the two get into a dogfight at a pet store. Meanwhile, Leonard makes a very "adult" purchase for Penny; and Emily catches Raj snooping in her apart (more…)There's trouble in paradise when Amy discovers Sheldon signed up for a one-way mission to colonize Mars, and the two get into a dogfight at a pet store. Meanwhile, Leonard makes a very "adult" purchase for Penny; and Emily catches Raj snooping in her apartment.

A speaking engagement at UC Berkeley puts Leonard and Sheldon in a galaxy not too far, far away from their idol George Lucas' Skywalker Ranch, and they consider dropping by. Meanwhile, Howard and Bernadette argue over what to do with his Doctor Who TARDIS (more…)A speaking engagement at UC Berkeley puts Leonard and Sheldon in a galaxy not too far, far away from their idol George Lucas' Skywalker Ranch, and they consider dropping by. Meanwhile, Howard and Bernadette argue over what to do with his Doctor Who TARDIS, so Raj and Amy try to settle things with a game of table tennis.

Sheldon shocks Amy with a startling revelation after she buys him a new laptop. Meanwhile, Raj throws Leonard and Howard under the bus after they lie to their wives and sneak off to an early screening of a movie.

In the Season 12 premiere, Sheldon and Amy's honeymoon runs aground in New York, while Penny and Leonard discover they are uncomfortably similar to Amy's parents, Mr. and Mrs. Fowler. Also, Koothrappali insults physicist Neil deGrasse Tyson and starts a Tw (more…)In the Season 12 premiere, Sheldon and Amy's honeymoon runs aground in New York, while Penny and Leonard discover they are uncomfortably similar to Amy's parents, Mr. and Mrs. Fowler. Also, Koothrappali insults physicist Neil deGrasse Tyson and starts a Twitter war.

Sheldon goes head-to-head with Wil Wheaton for the role of the new Professor Proton. Meanwhile, Penny steps in and takes care of Halley when Bernadette and Wolowitz both wind up on bed rest.

When Leonard learns Sheldon is the president of the tenants association, he decides to run against him. Also, Bernadette encourages Wolowitz and Koothrappali to find the owner of a drone after they find it in the backyard.

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 Bernadette improvise after Amy doesn't like the tame bachelorette party they plan (more…)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 Bernadette improvise after Amy doesn't like the tame bachelorette party they planned for her.

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 kids inadvertently infest Amy, Bernadette, Wolowitz and Koothrappali with pinkeye.

The Season 11 finale: When Amy's parents and Sheldon's family arrive for the wedding, everybody is focused on making sure all goes according to plan—everyone except the bride and groom.