The Big Bang Theory

Sheldon and Amy's honeymoon runs aground, while Penny and Leonard discover similarities with Amy's parents. Raj insults physicist Neil deGrasse Tyson.

Sheldon and Amy try to figure out what "perfect gift" Leonard and Penny gave them. Raj asks his father to arrange a marriage for him.

Stuart starts bringing his new girlfriend home, Penny and Leonard talk about starting a family, and Raj explores an arranged marriage.

Sheldon won't tell anyone why he's never mentioned his childhood friend Tam. Bernadette and Penny take out Raj's fiancée to get the skinny on her.

Amy doesn't have time to work on a project, so Sheldon goes to great lengths to ensure she can work with him, even if it means sabotaging her career.

When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation. Leonard is shocked that Penny doesn't remember their first kiss.

Leonard is caught in a tough spot when he's responsible for distributing extra grant money. Bernadette turns the backyard playhouse into a hideaway.

Sheldon tries to bond with Amy's father, but Howard lures Mr. Fowler away with magic tricks. Raj and Anu try to get physical for the first time.

Sheldon and Amy are devastated learning that Super Asymmetry has been discovered and disproven. Bernadette asks Denise to help her win a videogame.

A VHS tape inspires Sheldon to not give up on his and Amy's theory. Bernadette turns into a pageant mom over Howard's Magic Castle audition.

Penny and Leonard organise a paintball game that results in mayhem. Raj catches Anu with her ex, and Stuart doesn't want to move in with Denise.

Penny's ex, Zack, and his wife want a baby, but when Zack is infertile, they ask Leonard to help. Raj attempts to mend things with his ex-fiancée.

Sheldon and Amy's theory is proven by two physicists, who then try to kick Amy off the Nobel nomination. Bernadette has a big success at work.

Sheldon helps Bernadette and Howard navigate bureaucratic paperwork. 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 and his wife. Raj's cancelled bachelor party takes a turn.

The gang finds out Wil Wheaton hosts a celebrity Dungeons and Dragons game. Deception and betrayal are the path to make it to the one open seat.

While Bernadette is away and Howard is in charge of the kids, Sheldon finds a book on experimenting on kids. The guys plus Amy make a day of it.

Pemberton and Campbell charm America, so Sheldon and Amy bring Nobel laureates Kip Thorne, George Smoot and Frances Arnold to their side.

Amy has a meltdown due to the pressure associated with winning a Nobel Prize. Raj and Howard try to relive the good old days.

Raj is worried people won't take him seriously in his own field after publishing a paper that suggests he may have discovered alien life.

Kripke has proof that Dr. Pemberton plagiarized his thesis, and Sheldon and Amy aren't sure whether they should turn him in or not.

Leonard is surprised when Beverly is kind to him on a visit, until he finds out the real reason she's there. Denise and Stuart overstay their welcome.

Everything changes as Amy and Sheldon await big news. Howard and Bernadette leave their kids, while Leonard and Penny keep a secret.

Bernadette and Howard leave their kids, Penny and Leonard try to keep a secret, Sheldon and Amy stick together, and Raj makes a new friend.