Walter White, a high school chemistry teacher in Albuquerque, New Mexico, faces a life-altering crisis when he is diagnosed with terminal lung cancer. Struggling with the financial burdens of his impending medical treatments and the desire to secure his family's future, Walter decides to use his chemistry expertise to produce and sell high-quality methamphetamine. He partners with a former student, Jesse Pinkman, who has experience in the drug trade but lacks the skills to produce the product.
As Walter and Jesse enter the world of meth production, they encounter significant challenges, including rival drug dealers and the law enforcement authorities. Walter adopts the alias "Heisenberg" to protect his identity and develop a reputation in the drug underworld. Meanwhile, he struggles to maintain his façade as a devoted husband and father to his wife, Skyler, and their teenage son, Walter Jr., who has cerebral palsy. Skyler becomes suspicious of Walter's erratic behaviour and begins to investigate his activities.
Throughout the season, Walter's transformation from a mild-mannered teacher to a calculated criminal becomes increasingly pronounced. The duo faces moral dilemmas and dangerous encounters, particularly with a violent distributor named Tuco Salamanca. The season culminates in a high-stakes confrontation that forces Walter to take drastic actions to protect his new criminal enterprise and his family, setting the stage for the escalating conflict and consequences that will follow.
Walter White is a high school chemistry teacher who learns that he has lung cancer. With a new lease on life, Walter becomes a drug dealer to secure his family's financial security.
Following their debacle in the desert, Walter and Jesse are left with a mess to dispose of. Later, Skyler grows suspicious of Walt's recent activity.
Walter is left to deal with Krazy-8 alone following an argument with Jesse. After Marie raises concerns that Walt Jr. is smoking cannabis, Hank shows him the dangers of drug use.
The DEA becomes suspicious of a new drug kingpin. Walt reveals that he has cancer to Marie and Hank. Elsewhere, Jesse visits his estranged family.
Walter and Skyler attend a former colleague's party. Jesse tries free himself from the drugs. Later, Skyler organizes an intervention for Walt.
The side effects of chemo begin to plague Walt, who is also cooking meth again. Jesse's friend, Skinny Pete, introduces him to a distributor named Tuco, but things go awry and Jesse ends up hospitalised.
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.