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 the line crystal meth in a used RV, to provide for his family once he is gone.

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.

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 aunt discovers he has been smoking pot. Also, Skylar is upset when Walter stays away from home.

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 is the target of a depressed Walter's anger, and Jesse makes a surprise visit to his parents home.

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

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