The season 1 of ‘Big Bang Theory’ introduces to the viewers the main characters who reoccur through all the seasons. It consists of seventeen episodes. In the pilot of season one the protagonists Sheldon (
Jim Parsons) and Leonard (
Johnny Galecki) are seen in the corridor of a sperm bank. They had come there to donate their sperms so some child can have as high an IQ as them and to earn a little extra money to increase the bandwidth of their internet. They do not donate as Sheldon is hesitant. They go back to their apartment and find they have a new neighbour named Penny (
Kaley Cuoco). Leonard finds her very alluring and ends up inviting her for lunch with them.
Leonard and Sheldon tell Penny about their work, Penny tells them about her work and her ex-boyfriend. She tells that she is in such a mess and to top it all her shower is not working. Leonard spontaneously offers her their shower. Leonard and Sheldon discuss about their last time they had a woman in their apartment, it was Leonard’s grandmother. While they are talking Howard Wolowitz (
Simon Helberg) and Raj Koothrapali (KunalNayyar), enter their apartment talking about a Stephen Hawking lecture that he gave at MIT in 1974. Sheldon tells them that Leonard has a girl at their apartment to which Howard thinks it is Leonard’s grandmother. When he realises that there is a girl in their apartment, he asks Leonard if he is interested in having sex with her, to which Leonard immediately denies. Penny appears as she is not able to turn on the switch from tub to shower
She realises there are more people and greets them. Leonard helps her with the switch after which Penny asks him if he can do her a favour by collecting her TV from her ex-boyfriend’s place. Leonard and Sheldon go to Penny’s earlier apartment to find her ex-boyfriend to be an enormous man. He doesn’t treat both of them well; they go back in vain. Penny seeing them in their state apologises and says she will treat them to dinner. Leonard is trying to make Penny have a good impression on him. When Penny gets a package, he signs it and takes it to her apartment along with Sheldon. The unkempt state of Penny’s apartment disturbs Sheldon; he decides to help clean up her apartment. When Leonard sees Penny kissing another guy his hopes of having a relationship with her are shattered.He asks his colleague (Leslie Winkle) to go to with him but she turns him down, Leonard feels very dejected.
He decides to buy himself a cat, in a sincere attempt to stop Leonard from getting a cat Sheldon encourages him to ask Penny out on a date. Sheldon gets fired, and this leads him to have weird obsessions including ‘fixing eggs’ and weaving ponchos. Leonard is concerned about Sheldon’s behaviour and decides that there is only one person who can make him stop doing what he is doing – his mother. Leonard gets seduced by Leslie Winkle but what Leslie wants is a one night stand and nothing more. Leonard is not sure as he feels this might be a hindrance for him if he ever has a chance at Penny. Penny throws a Halloween party which everyone attends, including her ex-boyfriend (Kurt). Leonard’s feelings for Penny immensely increase in this situation. He tries to impress her by standing up to Kurt; this leads him to his humiliation. Penny’s friend from Nebraska visits her who is quickly seduced by Howard.
As Howard and Penny’s friend take over Penny’s apartment, she takes refuge in Sheldon’s and Leonard’s apartment. Penny gets enrolled as the fourth member of the guys’ Halo team as Wolowitz is engaged. Raj’s parents set him up on a date; Raj starts to panic as he can’t speak with women. Meanwhile, Penny, while practising her bartending skills discovers that Raj can talk to women when he has alcohol. Leonard and Sheldon get an opportunity to present a physics paper at a conference. Sheldon decides that he doesn’t want to go, whereas Leonard decides to go and hand in the paper by himself. Leonard’s decision infuriates Sheldon; Penny tries to make both of them talk to each other properly, but this only accelerates things. Leonard flimsily lies to Penny in an attempt to skip her musical performance. Sheldon becomes suspicious about this and constructs a much more elaborate lie leading to the appearance of his non-existing cousin.
Leonard leaves the apartment when Sheldon catches the flu as he wants to avoid taking care of him. Sheldon shows up Penny’s workplace – The Cheesecake Factory. Penny has no option but to take care of Sheldon. A 15-year-old physics prodigy Dennis Kim visits the University. Sheldon gets very intimidated by his work and decides to leave his career and concentrate on getting a Nobel Peace Prize. His friends seeing the dilemma Sheldon is in try to derail the boy genius’s progress.
The college conducted their Physics Bowl Tournament; Sheldon, Leonard, Howard and Raj enter it. Sheldon is not able to be a good team player;he gets thrown out of the team. The guys recruit Leslie Winkle as Sheldon’s substitute. Penny criticises Leonard and his geeky interests as everyone was transporting the time machine prop to their apartment which Leonard bought by accident. Sheldon’s twin sister, Missy,who is incredibly beautiful visits town, all the guys can’t avoid hitting on her. While everyone is at their work trying to impress, Missy; Leonard comes up with a strategy to eliminate the others. Sheldon decides that he should determine who dates his sister. Meanwhile, Raj takes a drug to avoid him from keeping quiet in front of women. Penny plans a surprise birthday party for Leonard as she realises that he has never celebrated his birthday.
Penny and Sheldon go to collect the present for Leonard, but it takes more time than expected. Howard takes drastic steps to stall Leonard in the meantime. Penny breaks up with her boyfriend as he posts personal things about her on his blog. When she turns to Leonard for his advice, he convinces her to get back with her ex-boyfriend. Penny gets angry with Leonard for giving her bad advice. Leonard asks Penny out on a date;she says ‘yes’. Both of them seek romantic advice from Sheldon.