This season the Big Bang gang’s romantic universe expands. On the rebound from Penny, Leonard falls into the arms of Raj’s sister Priya. Sheldon gets a girlfriend, or rather a friend who is a girl: Amy, a dour neurobiologist who declares herself besties with Penny. Howard and Bernadette heat up. And so do Raj and Bernadette (at least in Raj’s Bollywood daydream). All in the furtherance of award-winning genius comedy.
The superb sitcom The Big Bang Theory launches into its fourth season with an expanded cast and a whole new set of social dynamics to go with it. It's a little unsteady at first: Sheldon (the ever-inspired Jim Parsons) denies having a girlfriend in the similarly intellectual Amy Farrah Fowler (Mayim Bialik, a long way away from Blossom), which leads to several Sheldon-dominated episodes--and as marvelous a character as Sheldon is, he can be too much of a good thing. Fortunately, things soon take a clever turn: Penny (Kaley Cuoco), Howard's girlfriend Bernadette (Melissa Rauch), and Amy become, ever so awkwardly, friends, providing an ingenious counterpoint to the socially hapless quartet of Sheldon, Leonard (Johnny Galecki), Howard (Simon Helberg), and Raj (Kunal Nayyar). Amy's emotional disconnection but fervent curiosity provides a delicious variation on Sheldon (without in any way replacing him) that gooses the show up to a new level. But episodes without her are still enjoyable--this is one of the best-written and -acted comedies on television. Though there is an odd increase in bodily function humor (perhaps the writers are trying to counter the jokes about comic books and theoretical physics), inventive stories abound: Sheldon becoming obsessed with cats; Amy's complete bafflement at becoming aroused by one of Penny's ex-boyfriends; grappling with Wil Wheaton over 21 extra seconds of Raiders of the Lost Ark; the plundering of Sheldon's World of Warcraft account; Leonard getting involved with Raj's sister Priya (Aarti Mann), much to Raj's discomfort; and much, much more. The balance of the ensemble grows increasingly skillful over the episode, giving everyone a chance to shine. --Bret Fetzer