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.

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.

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

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 a baby shower.

Walt's secret is in jeopardy when Skyler thanks Gretchen for paying for his treatment.

Walt and Hank get into a heated argument at a party. Skyler opens up to her boss. Jane hides her relationship with Jesse from her father.

Walt faces a new threat, on a new front and deals with an increasingly angry Skyler, who must consider what to do next with her life and the kids. Meanwhile, Jesse comes face-to-face with some startling self-revelations.

Walt loses control as he reacts to Skyler's news, endangering his job and relationships with Saul and Jesse. Hank throws himself into his blue meth investigation. Jesse enacts a new plan.

Events set in motion long ago move toward a conclusion.