The Recombination Hypothesis - wikipedia The Recombination Hypothesis This is the current revision of this page, as edited by Aspects ( talk contribs ) at 18 : 28, 9 June 2017 ( Moved article into subcategory ). The present address ( URL ) is a permanent link to this version. Revision as of 18 : 28, 9 June 2017 by Aspects ( talk contribs ) ( Moved article into subcategory ) ( diff ) ← Previous revision Latest revision ( diff ) Newer revision → ( diff ) `` The Recombination Hypothesis '' The Big Bang Theory episode Episode no. Season 5 Episode 13 Directed by Mark Cendrowski Story by Chuck Lorre Teleplay by Bill Prady Steven Molaro Production code 3X6863 Original air date January 19, 2012 ( 2012 - 01 - 19 ) Running time 22 minutes Guest appearance ( s ) Jim Turner as Reverend White Episode chronology ← Previous `` The Shiny Trinket Maneuver '' Next → `` The Beta Test Initiation '' The Big Bang Theory ( season 5 ) List of The Big Bang Theory episodes `` The Recombination Hypothesis '' is the 100th episode of the American sitcom The Big Bang Theory and the 13th episode of the series ' fifth season. It premiered on CBS in the United States on January 19, 2012. In this episode, Leonard impulsively asks Penny out for dinner on a date. The story and concept of the episode was written by series co-creator Chuck Lorre. The teleplay was written by co-creator Bill Prady and writer Steven Molaro. `` The Recombination Hypothesis '' was directed by Mark Cendrowski. The episode received good reviews from television critics who spoke positive about Leonard and Penny trying to rework their relationship. Upon airing, `` The Recombination Hypothesis '' garnered 15.71 million viewers in the United States and 5.3 rating in the 18 -- 49 demographic, according to Nielsen ratings. Contents 1 Plot 2 Production 3 Reception 3.1 Ratings 3.2 Critical reception 4 References 5 External links Plot The episode begins with Sheldon receiving a cardboard cut - out of Spock he ordered, however is dismayed to find it is not the Spock played by Leonard Nimoy but rather Zachary Quinto. While Sheldon complains, Leonard sees Penny and they exchange smiles. Leonard walks over asking her if she has any plans for dinner. Penny looks surprised about being asked out on a date and accepts. Penny is trying on clothes with Amy and Bernadette. Penny acts nervous and Bernadette tells her that everything will work out great since Leonard is crazy about her. Whilst playing Settlers of Catan, Sheldon keeps asking for `` wood '' to build a road causing Howard and Raj to laugh at him not realizing the sexual innuendo. The gang asks Leonard why he is putting himself through another relationship with Penny. During dinner Leonard asks Penny whether there is a name for a first - date with someone you used to date and Penny replies `` awkward. '' They decide to make - believe like they are on a real first date. Leonard tells Penny about his work and that he built a Bat - Signal. Penny laughs and asks him if he is some kind of nerd. Leonard says that he is the `` King of the Nerds ''. If anyone displeases him, he will not help them set - up their printer. Leonard then asks Penny whether they are going to get back together. Shocked Penny confesses that she will always have feelings for him and that he always over thinks everything. Back at the apartment, Leonard charges in as his buddies tease him about his date ending at 8 : 30. Later Leonard is asleep and awakened by a text from Penny who meets him in the hallway, kisses him, takes him into her apartment and tells him to be quiet. Leonard wonders how a bad date ended in sex. Penny thought that things were great until he asked if they were getting back together. Leonard suggests that they treat their relationship like a new version of software, a `` Penny and Leonard 2.0 ''. They could try being together and not tell their friends until they know it is working. At The Cheesecake Factory, Bernadette is disappointed that things did not work out. Leonard sits down and starts a fight with Penny. Penny counters that he has to always be right. Sheldon thinks that Leonard is wrong more than anyone he knows. Leonard gets another early morning text. She demands to know why he was a jerk at work. They had agreed to be friends, not fight. Leonard heads toward her apartment because their new relationship was about sex after fighting. Later, Leonard asks Penny what exactly they are doing since every relationship scenario he plays out ends badly. Then Leonard hears Sheldon calling him. It turns out that Leonard was imagining everything, and he is still with Sheldon complaining about the Spock cardboard cut - out. Leonard decides that, despite the fact it seems that the relationship will once again end badly, he still wishes to ask Penny out. Penny asks whether he has thought things through. Leonard replies that he has and still thinks they should go ahead with it. Penny therefore agrees and then smiles. In Penny 's bedroom, she is again choosing an outfit for her date. Daydreaming she sees herself in a wedding dress and heavily pregnant. Penny rubs her belly and tells Leonard that it is too late to start saying no now. Penny wakes up, apologizes and the dream reminds her to go to the drugstore. Production `` The Recombination Hypothesis '' is first episode of a two episode arc featuring Leonard and Penny attempting to restart their relationship that has been one of the major plot lines and driving forces of the series. The arc concludes with the next episode `` The Beta Test Initiation '' where Penny and Leonard return from their date. The first scene is a salute to the original pilot where Leonard and Sheldon climb the stairs wearing similar outfits and they spot Penny through her apartment door wearing the same shirt from the pilot. Sheldon is disappointed to discover that a Mr. Spock cardboard stand - up he ordered is a portrayal of Zachary Quinto 's Spock not Leonard Nimoy 's Spock. According to Bill Prady, the co-creator of The Big Bang Theory, approval from Paramount, J.J. Abrams ( producer of the new Star Trek series ) and Zachary Quinto was required in order to mock Spock. Also, this is the first time that an entire episode is a `` dream - sequence '', a unique style of storytelling, and is the second Chuck Lorre show to achieve the `` dream - sequence '' story, after Two and a Half Men in the episode `` Frodo 's Headshots ''. Reception Ratings `` The Recombination Hypothesis '' was originally broadcast on January 19, 2012 in the United States between 8 : 00 p.m. and 8 : 30 p.m. Upon airing, `` The Recombination Hypothesis '' garnered 15.71 million viewers with the best ever ratings in the adults 25 - 54, adults 18 - 49 and adults 18 - 34 categories. Critical reception `` The Recombination Hypothesis ' '' received positive reviews from television commentators. R.L Shaffer of IGN gave the episode a `` really good '' review. The reviewer says the episode `` knocked it out of the park '' even though it started like `` another attempt to tease the anxiety of the Penny / Leonard relationship '' the final twist did show some growth in Leonard 's character that he must not over-think their relationship. Carla Day of TV Fanatic gave a positive review. Day noted that revisiting Leonard and Penny on the 100th episode was the best way to honor the history of the series. Though she was happy to see `` Peonard or Lenny '' back together, she felt that the other guys had the best lines with the `` wood '' jokes. Overall she found the show `` brought us back to the origins of the comedy and what made us fall in love with these nerds and their gorgeous neighbor. '' The Editor Rating was 4.7 out of 5.0. References Jump up ^ `` ' The Big Bang Theory ' 100th Episode : Penny And Leonard 2.0 Software Defined ''. January 20, 2012. Retrieved August 27, 2012. Jump up ^ `` The Big Bang Theory Episode : `` The Recombination Hypothesis '' ``. TV Guide. Retrieved August 27, 2012. ^ Jump up to : `` '' The Big Bang Theory '' The Recombination Hypothesis ( 2012 ) ``. IMDb. August 27, 2012. Retrieved August 27, 2012. Jump up ^ `` The Big Bang Theory - The Recombination Hypothesis ''. CBS Interactive. August 27, 2012. Retrieved August 27, 2012. ^ Jump up to : `` '' The Big Bang Theory '' Tops `` American Idol '' in Adults 18 - 49 and Adults 25 - 54 in Common Half - Hour ``. The Futon Critic. January 20, 2012. Retrieved September 7, 2012. ^ Jump up to : `` The Recombination Hypothesis ( 2012 ) Did You Know ? ''. IMDb. July 7, 2012. Retrieved July 7, 2012. Jump up ^ `` The Big Bang Theory : `` The Recombination Hypothesis '' Review ``. IGN. January 20, 2012. Retrieved July 7, 2012. Jump up ^ `` The Big Bang Theory Review : Penny and Leonard 2.0 ''. January 2, 2012. Retrieved July 7, 2012. External links `` The Recombination Hypothesis '' on IMDb `` The Recombination Hypothesis '' at TV.com The Big Bang Theory Characters Leonard Hofstadter Sheldon Cooper Penny Howard Wolowitz Raj Koothrappali Episodes Season 1 `` Pilot '' Season 2 `` The Terminator Decoupling '' Season 3 `` The Jiminy Conjecture '' Season 4 `` The Cruciferous Vegetable Amplification '' `` The Hot Troll Deviation '' `` The Love Car Displacement '' `` The Toast Derivation '' `` The Roommate Transmogrification '' Season 5 `` The Skank Reflex Analysis '' `` The Infestation Hypothesis '' `` The Wiggly Finger Catalyst '' `` The Russian Rocket Reaction '' `` The Rhinitis Revelation '' `` The Good Guy Fluctuation '' `` The Isolation Permutation '' `` The Flaming Spittoon Acquisition '' `` The Shiny Trinket Maneuver '' `` The Recombination Hypothesis '' `` The Beta Test Initiation '' `` The Werewolf Transformation '' `` The Hawking Excitation '' `` The Stag Convergence '' `` The Countdown Reflection '' Season 6 `` The Fish Guts Displacement '' `` The Santa Simulation '' `` The Egg Salad Equivalency '' Season 7 `` The Hofstadter Insufficiency '' `` The Convention Conundrum '' Season 8 `` The Locomotion Interruption '' Season 9 Season 10 Recurring concepts `` Soft Kitty '' Related articles Awards and nominations Bazinga ( genus ) Euglossa bazinga Young Sheldon Portal Category Book Retrieved from `` https://en.wikipedia.org/w/index.php?title=The_Recombination_Hypothesis&oldid=784716685 '' Categories : The Big Bang Theory episodes 2012 American television episodes Hidden categories : Use mdy dates from July 2012 Tv.com template using numeric id Talk Article Talk More Contents About Wikipedia This page was last edited on 9 June 2017, at 18 : 28. 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Question: when do leonard and penny start dating again
Answer: 13th episode of the series' fifth season