CBS

Season 4: Episode 4 - The Hot Troll Deviation

The Hot Troll Deviation: ­While the gang has dinner at the Cheesecake Factory one evening, Wolowitz sees Bernadette, who he hasn't spoken to since they broke up. He realizes how much he misses her and wants to get back together with her, when his fantasy girl Katee Sackhoff can't even keep his interest. He enlists Penny's help to get Bernadette back but she insists that Wolowitz tell her the reason they broke up in the first place - something he has never spoken about.

Meanwhile, Sheldon and Koothrapali deal with working together in the same office space. When Sheldon doesn't want to buy Raj his own desk for the office, Raj convinces Sheldon to let him buy one himself. He buys such an enormous desk and gets a rise out of Sheldon which leads to a battle of wills.