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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...

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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

    It turns out that Leonard, Howard and Raj didn't enjoy the time they spent trapped with Sheldon at the North Pole. In fact, they conspired to fake the results of his experiement, so they could get home sooner (it was that or kill him). When Sheldon realises his results are not of the Nobel Prize-winning quality he thought they were, he's far from happy.

  • 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. They agree to be friends but find it difficult to switch off their romantic feelings for each other. Sheldon and Howard make a bet to determine a species of cricket.

  • Howard Wolowitz as a goth

    Episode 3 - The Gothowitz Deviation

    When Penny's bed breaks, she ends up spending a lot more time in Leonard and Sheldon's flat - to Sheldon's immense displeasure. So in order to mould Penny into the perfect houseguest, Sheldon uses some well-calculated chocolate rewards.

    Meanwhile, Howard and Raj go to a goth nightclub. They meet two women and things seem to be going well until the ladies take the two friends along to a tattoo parlour.

  • Raj and Sheldon

    Episode 4 - The Pirate Solution

    Raj must find a job or he'll be sent back to India. Sheldon suggests that Raj work for him rather than with him, and Raj begrudgingly accepts the offer. Howard gets lonely when Raj starts working with Sheldon and hangs out with Leonard and Penny - who long to be left alone.

  • Sheldon screaming angrily

    Episode 5 - The Creepy Candy Corollary

    Sheldon enters a competition that pits him sagainst 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

    Leonard worries that he will never fit in with Penny's friends unless he shows an interest in football, but, as luck would have it, Sheldon is an expert on account of growing up in Texas (where an interest in football is basically mandatory). Meanwhile, Raj falls out with Howard after Howard's lady-chasing antics result in the tragic loss of a kite.

  • Leonard

    Episode 7 - The Guitarist Amplification

    When Leonard discovers that Penny plans on having a male friend - who's 'definitely not gay' - stay with her for several weeks, he gets jealous and they end up arguing. The bad atmosphere reminds Sheldon of his parents feuding when he was a child, resulting in him reverting back to a child-like state of bewilderment.

  • Howard on the ground

    Episode 8 - The Adhesive Duck Deficiency

    While Leonard, Howard and Raj pitch tent to watch a meteor shower out int he wilderness, Sheldon remains at the flat to enage in far worthier pursuits. That is, until Penny slips in the shower prompting Sheldon to come a heroic rescue.

  • Raj, Leonard and Howard

    Episode 9 - The Vengeance Formulation

    Howard is scared about committing to Bernadette and so avoids her. He realises he's made a mistake and to compensate, proposes marriage. Meanwhile, Barry Kripke plays a prank on Sheldon during a radio interview, humiliating him in front of the nation. Sheldon responds by plotting the ultimate revenge.

  • Penny with food in her mouth

    Episode 10 - The Gorilla Experiment

    Penny feels left out when Bernadette shows an interest in science and asks Sheldon to teach her more about the subject. Eventually, she surprises everyone with what she's learned. Meanwhile, Woolowitz is jealous when Bernadette asks Leonard about his work. Sensing his jealous streak, Bernadette threatens to break up with him.

  • Beverley hugging Leonard

    Episode 11 - The Maternal Congruence

    Following another visit from his mother, Leonard begins to feel insecure when he discovers that she's closer to Sheldon than she is to him. Penny meanwhile attempts to befriend her - with a little help from alochol.

  • Raj and Sheldon

    Episode 12 - The Psychic Vortex

    When Leonard ridicules Penny's belief in psychics, their relationship takes a turn for the worse. Meanwhile, on account of Leonard and Howard both having girlfriends, Raj is forced to resort to Sheldon as a 'wingman' for chatting up girls - with surprising success.

  • Penny in a net

    Episode 13 - The Bozeman Reaction

    Leonard and Sheldon's flat is burgled. Determined to out-wit 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 flummoxed by a formula he's working on so gets a less mentally taxing job at the Cheesecake Factory to kickstart his creativity.

    Penny objects but Sheldon is surprising everybody by being competent in his new role. But will he be able to solve his formula?

  • Leonard and Sheldon

    Episode 15 - The Large Hadron Collision

    Leonard is invited to Switzerland on Valentine's Day to see the world's largest particle accelerator.

    Sheldon is gutted when Leonard asks Penny to go with him, as a Valentine's Day treat, instead of him. Sheldon tries to coerce the couple into letting him take Penny's place, will they relent and let him go?

  • Sheldon in a cell

    Episode 16 - The Excelsior Acquisition

    Sheldon is summoned to court for driving through a red light while taking Penny to hospital in an earlier episode. He misses meeting Stan Lee, creator of Spiderman, at the comic book store and riles the judge so much that he ends up in prison.

    Will Sheldon be released from prison? Will the gang get to meet Stan Lee in Sheldon's absence?

  • Sheldon as Gollum

    Episode 17 - The Precious Fragmentation

    The gang squabble over a ring which they believe was used in The Lord of the Rings; Leonard wants to give it back to its original owner, Koothrappali wants to sell it so that he can buy a jet ski but Sheldon becomes obsessed with the ring and starts to turn into Gollum from The Lord of the Rings.

    Can the friends reach an agreement and will Sheldon shake his obsession?

  • Pantsless Sheldon

    Episode 18 - The Pants Alternative

    Sheldon has been awarded a prestigious prize by the university but is scared of collecting the gong at a ceremony because he knows he'll have to give a speech.

    Penny tries to gee Sheldon up using rousing references to X-Men and Leonard and Koothrappali offer psychological guidance without much success. On the night, Sheldon's nerves get the better of him and he has a drink before going on stage. Will he manage to make the stirring speech he's been preparing?

  • Sheldon and his arch nemesis

    Episode 19 - The Wheaton Recurrence

    Leonard tells Penny that he loves her but doesn't get the response he would have liked. The gang go bowling and get a surprise when Sheldon's enemy, Star Trek actor Wil Wheaton (cameo), is playing in the opposing team. Will Sheldon get revenge on Wil?

  • Penny at dinner with Sheldon

    Episode 20 - The Spaghetti Catalyst

    Sheldon tries to hide his friendship with Penny from Leonard but it isn't long before his double life is exposed to Penny and Leonard. Can Penny and Leonard keep their friendships with Sheldon without hurting each other?

  • Sheldon, Professor Plimpton and Leonard

    Episode 21 - The Plimpton Stimulation

    Sheldon meets a famous physicist online and invites her over to the flat. Once there, she flirts with Leonard and pays a visit to him in his bedroom.

    Penny finds out and confronts Leonard. Meanwhile Sheldon is irked that Leonard is showing interest in his friend. Can they resolve the matter?

  • Sheldon and Leonard

    Episode 22 - The Staircase Implementation

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

  • Howard and Raj

    Episode 23 - The Lunar Excitation

    Raj and Howard register Sheldon for online dating and find the perfect woman; the female version of Sheldon.

    Meanwhile, Penny seduces Leonard while she's drunk but regrets it the next day. How will Leonard react to their encounter?

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...

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The Junior Professor Solution

When Sheldon is forced to teach a course at the university, Howard surprises everyone by enrolling on it.

E4 8.30pm Thur 30 Oct