Penny’s criticism of Wolowitz’s romantic life pushes him into depression and AWOL for a fighting robot battle the rest of guys are depending on him for.

Penny starts dating Leonard’s handsome colleague; Leonard and his friends are tortured by Sheldon’s obsession with gift-giving etiquette.

Leonard asks Penny for advice when his new relationship starts moving too fast.

Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon’s stringent standards.

Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.

When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.

Sheldon and the gang are confused when a young grad student is attracted to him.

Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.

Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.

Sheldon creates a monster when he introduces Penny to online gaming.

A jealous Leonard reacts to Penny’s new guy by rebounding with Leslie.

Penny’s first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.

Walter accepts his new identity as a drug dealer after a PTA meeting. Elsewhere, Jesse decides to put his aunt’s house on the market and Skyler is the recipient of…

The side effects of chemo begin to plague Walt. Meanwhile, the DEA rounds up suspected dealers.

Walter and Skyler attend a former colleague’s party. Jesse tries to free himself from the drugs, while Skyler organizes an intervention.

Walter finally tells his family that he has been stricken with cancer. Meanwhile, the DEA believes Albuquerque has a new, big time player to worry about. Meanwhile, a worthy recipient…

Walter fights with Jesse over his drug use, causing him to leave Walter alone with their captive, Krazy-8. Meanwhile, Hank has a scared straight moment with Walter Jr. after his…

Walt and Jesse attempt to tie up loose ends. The desperate situation gets more complicated with the flip of a coin. Walt’s wife, Skyler, becomes suspicious of Walt’s strange behavior.

When an unassuming high school chemistry teacher discovers he has a rare form of lung cancer, he decides to team up with a former student and create a top of…