Whether on or above Earth, hilarity is outrageously universal in TV's most popular comedy featuring four forward-thinking but socially backward geniuses. Fun discoveries multiply: Leonard learns jealousy is bad for a relationship (with Penny) but science is good for seduction (of Penny). Howard finds life in the International Space Station life is no escape from terrestrial turmoil between his mom and his new wife Bernadette. Raj meets someone special who may be a good match, if he can keep her from fleeing mid-date. And then there's Sheldon. He learns what not to say after facing harassment charges or competing for tenure at work and how Dungeons & Dragons can be the icebreaker his relationship with Amy needs.
Episode 1
With his friends on dates, Raj must face his loneliness. Also, Wolowitz is caught in an argument between Bernadette and his mom, even while he’s in space.
Episode 2
When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.
Episode 3
Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz.
Episode 4
When Wolowitz returns from space, he doesn’t get the hero’s welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.
Episode 5
The gang celebrates Halloween at Stuart’s comic book store. Meanwhile, Leonard seduces Penny with science.
Episode 6
Sheldon’s relationship with Stephen Hawking is threatened over a game of “Words with Friends,” and Penny secretly enrolls in a class at the local college.
Episode 7
Wolowitz struggles with moving out of his mother’s house. Meanwhile, Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.
Episode 8
Raj and Howard try to to figure out why Sheldon disappears at 2:45 every afternoon; jealousy arises in Penny and Leonard's relationship.
Episode 9
When the University reassigns Sheldon’s parking spot to Wolowitz, their fight affects the whole gang.
Episode 10
When Amy gets sick, Sheldon tries to nurse her back to health; Wolowitz and his father-in-law plan a fishing trip.
Episode 11
During a Dungeons and Dragons game, Sheldon revisits Christmas memories; Amy, Penny and Bernadette look for a date for Raj.
Episode 12
When Sheldon is accused of sexual harassment, he ends up getting Raj, Leonard and Howard in trouble.
Episode 13
As the guys don costumes and go on a road trip to a comic book convention, the ladies decide to stay home and try to interpret a comic book.
Episode 14
Sheldon faces a crisis of confidence when he is forced to work with his nemesis, Barry Kripke; Raj and Howard buy expensive action figures of themselves.
Episode 15
A fight between Sheldon and Leonard impacts Amy and Penny's living arrangements; while Howard is away, Raj helps Mrs. Wolowitz out.
Episode 16
The guys search for a perfect Valentine's Day gift for their significant others; Stuart and Raj host a "lonely people" party at the comic book store.
Episode 17
After a bad date, Koothrappali decides to never leave his apartment; Penny's acting skills impress Sheldon.
Episode 18
Leonard, Sheldon and Howard give lectures on science to junior high students. The girls ditch work to go to Disneyland. Raj devises a date for Lucy that fixes their social anxiety problems.
Episode 19
Howard considers whether or not he should open a letter from his father; Penny and Leonard host a "grown-up" cocktail party.
Episode 20
The girls get involved when Leonard, Sheldon and Raj compete for tenure at the University.
Episode 21
Amy tries to help Sheldon get over his compulsive need for closure when one of his favorite TV shows is canceled; Raj discovers a secret about Lucy.
Episode 22
Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform; Bernadette and Howard run into trouble while dog-sitting for Raj's pet.
Episode 23
A date between Raj and Lucy takes both of them out of their comfort zones. After a trip to Las Vegas goes awry, the girls join in on a Dungeons and Dragons game, which causes Amy and Sheldon to re-evaluate their relationship.
Episode 24
When Leonard receives an exciting opportunity to work overseas, Penny and Sheldon are thrown for a loop. Raj and Lucy's relationship comes to a crossroad.