A visit from Raj's sister coincides with Leonard becoming secretive.
Season 4 Episode 6 of The Big Bang Theory resulted in a 0.00 rating in the 18-49 demographic.
s04e01 - The Robotic Manipulation
s04e02 - The Cruciferous Vegetable Amplification
s04e03 - The Zazzy Substitution
s04e04 - The Hot Troll Deviation
s04e05 - The Desperation Emanation
s04e06 - The Irish Pub Formulation
s04e07 - The Apology Insufficiency
s04e08 - The 21-second Excitation
s04e09 - The Boyfriend Complexity
s04e10 - The Alien Parasite Hypothesis
s04e11 - The Justice League Recombination
s04e12 - The Bus Pants Utilization
s04e13 - The Love Car Displacement
s04e14 - The Thespian Catalyst
s04e15 - The Benefactor Factor
s04e16 - The Cohabitation Formulation
s04e17 - The Toast Derivation
s04e18 - The Prestidigitation Approximation
s04e19 - The Zarnecki Incursion
s04e20 - The Herb Garden Germination
s04e21 - The Agreement Dissection
s04e22 - The Wildebeest Implementation
s04e23 - The Engagement Reaction
s04e24 - The Roomate Transmogrfication
The Big Bang Theory is a comedy series about four young scientists who know all about the world of physics, and one girl, who gives the physics world a real spin.
Leonard Hofstadter is a smart guy who tries his best to complete his research and become famous for his work while also attempting to be the most socially-interacting guy in their friend group. Sheldon Cooper is one of the world's smartest men with an intellectual capacity through the roof and a language with scientific words normal people only have one comment to ('What-). Howard Wolowitz is an engineer with his mind partially on science, but mostly on women. He always tries his best to impress a girl and get his share of sexual intercourses, but he always manages to screw up somehow, probably with his bad knowledge of treating women in a bad matter. Rajesh Koothrappali is an Indian scientist performing experiments on black holes, outer space, life on other planets and not to mention string theory. Raj is mostly known for his Selective Mutism, in other words, his fear of speaking to women, making social interaction difficult for him. Finally, there's Penny.
Penny is the gorgeous girl next-door to Leonard and Sheldon's apartment, and though she does not have any knowledge in physics or science, she makes success by being a funny character frequently having hilarious comments and on- and off-going relationships.