Sheldon gets in trouble with Amy when he isn’t impressed by her recent accomplishment, and Howard must come to grips with Bernadette’s dislike of children.

A cute comic book artist puts Leonard and Priya’s relationship to the test, while Sheldon tries to scare the guys for Halloween.

Amy becomes heartbroken when she discovers that Penny and Bernadette went wedding dress shopping without her.

Leonard and Penny try hanging out as friends on a ‘non-date’, but end up purposely ruining each others chances with perspective dates. Meanwhile, Sheldon enlists the help of Bernadette and…

Penny plays Matchmaker for Raj, which results in him finding a girl he is comfortable talking to.

Sheldon and Leonard get invited to a party at Wil Wheaton’s house, and Howard gets an out-of-this-world opportunity.

Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.

Sheldon’s mother, Mary Cooper, comes to visit, but Sheldon is annoyed that she also spends time with the rest of the gang, instead of catering to his every demand.

Penny is worried with how damaged her friendship with the guys will be in the aftermath of her sleeping with Raj while Sheldon becomes the leader of the paintball team.

A fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

When Howard finally breaks the news to his mom that he’s engaged to Bernadette, it lands her in the hospital.

When Bernadette receives her PhD, Wolowitz feels emasculated. Raj and Leonard swap places and Penny does something she’s regrets.

Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.

When Leonard spends too much time in the shower with Priya, Sheldon charges Leonard with two violations of the roommate agreement. However, before he can get too far, Priya uses…

Sheldon and Amy decide to start several rumors about the others as a test. Meanwhile, Howard takes his relationship with Bernadette to even higher level.

Sheldon is baffled by Wolowitz’s magic trick. Meanwhile, Leonard realizes dating Priya may make it impossible to continue being friends with Penny.

Sheldon becomes concerned when everybody begins to hang out at Raj’s apartment and discovers Leonard is the center of the group.

Sheldon’s online-game account is hacked by Todd Zarnecki, who then proceeds to steal all his items prompting the guys to go on a quest to retrieve them. Penny, Bernadette and…

As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj’s sister.

A wealthy donor to the university makes Leonard consider how far he’s willing to go for the sake of science.

Hoping it will make him a better teacher, Sheldon has Penny give him acting lessons. Raj has fantasies about a friend’s girlfriend.

Bernadette runs into her ex-boyfriend while attending a science event with Wolowitz.

Leonard’s idea for a smartphone app derails his friendship with Sheldon.

The guys find a “super” use for Penny’s new boyfriend, Zack, when they enter a costume contest as the Justice League.

Amy finds she has sexual feelings for Penny’s ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.

Sheldon’s answers during an FBI interview put Wolowitz’s security clearance in jeopardy.

Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.

While the guys camp in line for a long-awaited movie screening, Penny and Bernadette invite Amy to her first slumber party.

Leonard keeps an affair a secret from Sheldon, Howard and Raj.

An embarrassing secret of Wolowitz’s comes to light, while Sheldon and Raj have a small war at work.

The guys are concerned as Sheldon searches for an alternative to human companionship.

Leonard realizes he’s the only one without a girlfriend, while Sheldon wants to get rid of his.

Realizing he will not live long enough to download his consciousness into a robot body, Sheldon tries to extend his life span.

Penny tags along on Sheldon’s first ever date; Wolowitz finds a new use for a robotic arm.

When Leonard and Penny aren’t speaking, Sheldon goes to extremes to keep them both happy.

Leonard and Sheldon compete for the attention of a famous female physicist.

Leonard tells Penny about how he met Sheldon for the first time…and what happened to the elevator.

While Penny worries that dating Leonard has ruined her for normal guys, Wolowitz and Koothrappali search for Sheldon’s perfect match online.

When the guys find a ring from “The Lord of the Rings” at a garage sale, it threatens to tear them apart.

Sheldon’s friends come to his aid when his fear of public speaking stands between him and a coveted award.