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 5 Summary

This series brings the sound of wedding bells and more is discovered about the complicated lives of Sheldon, Leonard and their socially dysfunctional friends.

  • S5Ep1-40d-image

    Episode 1 - The Skank Reflex Analysis

    Penny worries that she's screwed things up with her friends after her night with Raj. Meanwhile Sheldon takes command of the paintball team.

  • The Big Bang Theory: Sheldon

    Episode 2 - The Infestation Hypothesis

    A battle of wills between Sheldon and Penny leaves Amy in the middle. Leonard tries to spice up his long-distance relationship with Priya.

  • The Big Bang Theory

    Episode 3 - The Pulled Groin Extrapolation

    Leonard goes as Amy's date to a colleague's wedding. Howard tries to convince Bernadette to live with his mum after they get married.

  • The Big Bang Theory: Leonard

    Episode 4 - The Wiggly Finger Catalyst

    Raj is upset that he's the only one of the four guys not in a relationship, so Penny sets out to find him the perfect date.

  • The Big Bang Theory: Penny

    Episode 5 - The Russian Rocket Reaction

    Sheldon's old nemesis Wil Wheaton returns and invites everyone to a housewarming party. Sheldon threatens to 'de-friend' Leonard if he goes.

  • big bang theory

    Episode 6 - The Rhinitis Revelation

    Sheldon's mum visits and soon becomes a firm favourite with his friends, much to Sheldon's annoyance.

  • The Big Bang Theory: Leonard and Bernadette

    Episode 7 - The Good Guy Fluctuation

    Leonard questions his feelings for Priya when he kisses a girl he meets in the comic book store.

  • The Big Bang Theory: Sheldon

    Episode 8 - The Isolation Permutation

    Amy is heartbroken when she finds out that Penny and Bernadette have been shopping for bridesmaids dresses without her.

  • The Big Bang Theory: Amy and Bernadette

    Episode 9 - The Ornithophobia Diffusion

    Leonard and Penny attempt to hang out without anybody else around, while Sheldon faces his fear of birds.

  • The Big Bang Theory: Howard

    Episode 10 - The Flaming Spittoon Acquisition

    Stuart from the comic book shop asks Amy out on a date. In jealousy, Sheldon asks her to be his girlfriend.

  • The Big Bang Theory: Sheldon and Bernadette

    Episode 11 - The Speckerman Recurrence

    Leonard confronts the man who bullied him in high school, while Penny realises she did her fair share of tormenting in the past.

  • Howard and Bernadette

    Episode 12 - The Shiny Trinket Maneuver

    When Sheldon is dismissive of Amy's career progress, Penny, Raj and Leonard try to make him realise that it's beneficial to a relationship to pretend to care about things, even if you aren't really that interested.

    Howard notices that Bernadette can't stand being around children when the two of them perform a magic show at his nephew's birthday party.

  • Penny

    Episode 13 - The Recombination Hypothesis

    In the 100th episode of the US sitcom, Leonard decides to ask Penny out on a date, and they both agree to give their relationship another chance.

    They argue over dinner and remember why things didn't work out between them in the first place, but end up sleeping together anyway.

    Later they agree to continue seeing each other secretly, on the condition that they act like friends when everyone else is around, just to make sure that the relationship works this time.

  • The Big Bang Theory

    Episode 14 - The Beta Test Initiation

    Leonard and Penny decide to put their relationship through a 'beta test', allowing them to report the problems they have with each other as 'bugs'.

    However, when lengthy lists of relationship bugs are exchanged, Leonard takes it to heart and decides to treat Penny to a 'real date' at a firing range.

  • Leonard and Sheldon

    Episode 15 - The Friendship Contraction

    After Sheldon keeps Leonard awake all night, Leonard decides that he needs a break from Sheldon's thankless demands and the Roommate Agreement is formally broken, ending the friendship between them.

    While preparing to go on a flight to the International Space Station, Howard enlists Raj's help to make sure that he gets a cool astronaut nickname like the rest of the crew.

  • Leonard and Penny

    Episode 16 - The Vacation Solution

    Sheldon is forced to use up his two weeks of holiday time from work, so he spends his fortnight off helping Amy in her biology lab.

    He complains that the tasks she gives him to do are menial and boring, but when she finally relents and asks him to dissect a brain, he cuts his thumb open and passes out.

    When Bernadette asks Howard to sign a pre-nuptial agreement before their wedding, Penny grows curious about Leonard's feelings on the subject.

  • Amy

    Episode 17 - The Rothman Disintegration

    When Sheldon and Kripke argue over who should get Professor Rothman's vacant corner office, Leonard, Raj and Howard devise a contest to settle the issue with the office as the winning prize.

    Unfortunately, the contest has a sporting theme, and both Sheldon and Kripke are terrible at sports.

    Meanwhile, Amy buys Penny a painting to celebrate their friendship, but Penny hates the garish artwork and discreetly attempts to dispose of it, with help from Bernadette.

  • Bernadette

    Episode 18 - The Werewolf Transformation

    Sheldon's well-organised world is turned upside down when he learns that the barber who has cut his hair for years has passed away.

    As his orderly routines descend into chaos, he is forced to act like a hippy in order to match his shaggy new hairstyle.

    Howard is sent to Houston for the gruelling NASA training programme and shares horrific stories about his experiences with Bernadette via Skype.

  • The Big Bang Theory: Amy and Sheldon

    Episode 19 - The Weekend Vortex

    Amy gets upset with Sheldon when he breaks his promise to accompany her to her aunt's birthday party and instead opts to join the guys for a Star Wars video game marathon lasting the entire weekend.

    Later, Penny convinces Amy that she should confront Sheldon about the matter and demand an apology.

  • The Big Bang Theory: Sheldon

    Episode 20 - The Transporter Malfunction

    Penny buys Leonard and Sheldon some Star Trek memorabilia, but she is irked when they refuse to play with the toys in case removing them from the packaging diminishes their value.

    Later, prompted by a guilty conscience, Sheldon dreams that one of his Star Trek figures is developing a life of its own.

    Meanwhile, desperate to find a 'plus one' to take to a wedding, Raj finally gives up and asks his parents to set him up with a date.

  • The Big Bang Theory: Stephen Hawking and Sheldon

    Episode 21 - The Hawking Excitation

    Stephen Hawking comes to lecture at the university for a week, and Wolowitz is given the task of maintaining his wheelchair, making Sheldon green with envy.

    When Sheldon begs Wolowitz to introduce him to his hero Hawking, Wolowitz takes full advantage and only agrees after making Sheldon carry out a series of humiliating tasks, including doing his laundry, cleaning his room, and taking his mother dress shopping.

  • The Big Bang Theory

    Episode 22 - The Stag Convergence

    Leonard, Sheldon and Koothrappali throw a classy bachelor party for Wolowitz, during which some stories about the future bridegroom's colourful sexual history are accidentally revealed.

    When Bernadette hears about it, she becomes upset and threatens to call off the wedding. Can Wolowitz win her over with a convincing explanation and a heartfelt apology to get the nuptials back on track?

  • The Big Bang Theory

    Episode 23 - The Launch Acceleration

    When NASA tells a nervous Wolowitz that his space mission has been rescheduled, he tries to use the wedding as an excuse not to go.

    But he's forced to agree when he realises that Bernadette's father only likes him because he's an astronaut.

    Amy develops a cunning psychological plan to bring Sheldon closer. Meanwhile, Penny agrees to sleep with Leonard again, but freaks out when he accidentally asks her to marry him in the middle of the act.

  • The Big Bang Theory: Leonard and Sheldon

    Episode 24 - The Countdown Reflection

    Bernadette decides that she wants to be married to Wolowitz before his NASA space mission takes place. They scramble to organise a wedding ceremony at City Hall in the short time available, but their plans go awry.

    Can their friends find them an ordained minister and a romantic wedding venue before it's too late? All is revealed as the gang gather round the TV to watch the Space Shuttle, with Wolowitz on board, preparing to launch...

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

2 Episodes

Next on TV

The First Pitch Insufficiency

Howard is nervous when NASA asks him to throw the first pitch at a baseball game for National Space Day. Sheldon claims that he and Amy have a superior…

E4 8.30pm Thur 6 Nov

Our Picks Tonight

See all TV listings