The fourth season of The Big Bang Theory finds Leonard (Johnny Galecki) falling for Raj's sister Priya following his break-up with Penny (Kaley Cuoco). Meanwhile, Sheldon (Simon Helberg) finds romance with a neurologist who quickly establishes herself as Penny's new best friend. As Howard and Bernadette's relationship blossoms, Bernadette finds herself plagued by Bollywood daydreams starring Raj (Kunal Nayyar).
It seems that some of the umph that this show started with toned down a bit. At least we still have the main 5 Penny, Sheldon, Leonard, Raj and Howard, at points, show that they do have lives of their own, and yet get back together for one hilarious camaraderie.