Episode Guides

Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...

About the Show

Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...

Series 3 Summary

Leonard, Sheldon, Howard and Raj return from their expedition to the North Pole, and revert back to (relatively) normal life. Leonard continues to pine over Penny - only with a little more success this time around - while Sheldon carries on broadcasting his unmatched and unwelcome genius to everyone in earshot.

  • A bearded Leonard and Sheldon

    Episode 1 - The Electric Can Opener Fluctuation

    Leonard's attempts to woo Penny are constantly thwarted, while Sheldon heads to Texas after learning that his friends meddled with his expedition data

  • Howard, Sheldon and Raj squeezing through a door

    Episode 2 - The Jiminy Conjecture

    Leonard and Penny feel awkward around each other after their romantic liaison, while Sheldon and Howard take bets to determine a species of cricket

  • Howard Wolowitz as a goth

    Episode 3 - The Gothowitz Deviation

    Sheldon rewards Penny with chocolate to modify her behaviour, while Howard and Raj go to a goth nightclub

  • Raj and Sheldon

    Episode 4 - The Pirate Solution

    Raj reluctantly accepts a job offer from Sheldon so that he won't be sent back to India. Leonard and Penny try to get some time for themselves.

  • Sheldon screaming angrily

    Episode 5 - The Creepy Candy Corollary

    Sheldon enters a competition that pits him against Star Trek actor Wil Wheaton, whom Sheldon considers his arch-enemy after he snubbed him as a child at a Star Trek convention

  • Leonard in a football shirt, and Penny

    Episode 6 - The Cornhusker Vortex

    Sheldon teaches Leonard about football so that he can fit in with Penny's friends, but Leonard alienates the group with his new knowledge

  • Leonard

    Episode 7 - The Guitarist Amplification

    Sheldon is upset when Leonard and Penny argue about Penny's male friend staying over and he has to act as peacemaker

  • Howard on the ground

    Episode 8 - The Adhesive Duck Deficiency

    Leonard, Raj and Howard go on a camping trip that alters their minds. Sheldon has to come to Penny's rescue after she dislocates her shoulder when she slips in the shower.

  • Raj, Leonard and Howard

    Episode 9 - The Vengeance Formulation

    Howard is scared about committing to Bernadette so he avoids her. Then he realises he's made a mistake and, to compensate, he proposes to her.

  • Penny with food in her mouth

    Episode 10 - The Gorilla Experiment

    Penny feels left out when Bernadette asks Sheldon to teach her about science. And Howard is jealous when Bernadette asks Leonard about his work.

  • Beverley hugging Leonard

    Episode 11 - The Maternal Congruence

    Leonard is horrified when his mother turns up unannounced, and then he finds out that Sheldon knew about the visit

  • Raj and Sheldon

    Episode 12 - The Psychic Vortex

    Sheldon and Raj go to a university party, Leonard disapproves of Penny's belief in psychics, and Raj lusts after a girl called Abby

  • Penny in a net

    Episode 13 - The Bozeman Reaction

    Leonard and Sheldon's flat is burgled. Determined to outwit any thieves, the gang work on creating a state-of-the-art security system to protect the apartment. Can they deter the burglars?

  • Penny and Sheldon

    Episode 14 - The Einstein Approximation

    Sheldon is baffled by a formula he's working on, so he gets a less mentally taxing job at the Cheesecake Factory to kick-start his creativity

  • Leonard and Sheldon

    Episode 15 - The Large Hadron Collision

    Sheldon is gutted when Leonard asks Penny to go to Switzerland to see the world's largest particle accelerator instead of him

  • Sheldon in a cell

    Episode 16 - The Excelsior Acquisition

    Sheldon is summoned to court for driving through a red light. He misses the chance to meet Stan Lee and riles the judge. Will he go to prison?

  • Sheldon as Gollum

    Episode 17 - The Precious Fragmentation

    The gang squabble over a ring that they believe was used in The Lord of the Rings movies, while Sheldon seems to be turning into Gollum

  • Pantsless Sheldon

    Episode 18 - The Pants Alternative

    Sheldon earns a prestigious prize but is scared of collecting the award at a ceremony because he knows he'll have to make a speech

  • Sheldon and his arch nemesis

    Episode 19 - The Wheaton Recurrence

    Leonard tells Penny that he loves her. The gang go bowling and find that Sheldon's enemy Wil Wheaton is playing in the opposing team.

  • Penny at dinner with Sheldon

    Episode 20 - The Spaghetti Catalyst

    Sheldon hides his friendship with Penny from Leonard but his cover is soon blown. Can he remain friends with both Penny and Leonard?

  • Sheldon, Professor Plimpton and Leonard

    Episode 21 - The Plimpton Stimulation

    Sheldon meets a famous physicist online and invites her over to the flat, where she spends her time flirting with Leonard

  • Sheldon and Leonard

    Episode 22 - The Staircase Implementation

    This episode flashes back to the start of Sheldon and Leonard's friendship seven years previously and explains the housemate agreement

  • Howard and Raj

    Episode 23 - The Lunar Excitation

    Raj registers Sheldon for online dating and finds the perfect match: the female version of Sheldon. Penny seduces Leonard while she's drunk.

The Big Bang Theory synopsis

Arch-nerds Leonard and Sheldon may know more than their fair share about subatomic particles, but when it comes to people in general, and women in particular, they're absolutely clueless...

Episode Guide >

Catch up on 4oD

3 Episodes

Next on TV

The Bath Item Gift Hypothesis

At Christmas, Leonard's handsome colleague starts dating Penny, while Sheldon's obsession with gift-giving etiquette torments his friends

Channel 4 12.30pm Sun 21 Dec