Season synopsis
Contains spoilers for this season and earlier seasons.
Walter White, an Albuquerque chemistry teacher, learns he has inoperable lung cancer and worries about his pregnant wife Skyler and son Walter Jr. On a DEA ride-along with brother-in-law Hank Schrader, he spots former student Jesse Pinkman escaping a meth lab. Walter proposes they cook together, using his chemistry skills and Jesse's contacts. Their first RV cook produces unusually pure meth, but its first sale to dealers Emilio and Krazy-8 turns violent. Walter must use chemistry to survive, and Krazy-8 remains alive in Jesse's basement.
Walter and Jesse imprison the injured Krazy-8 in Jesse's basement. Walter debates whether to release him, then discovers Krazy-8 plans to kill him and strangles him with a bicycle lock. He returns to teaching and family life while hiding the killing. Walter tells Skyler that Jesse sells him marijuana, giving her a false explanation for their connection and prompting her to confront Jesse. Cancer treatment becomes another point of conflict: former partners Elliott and Gretchen offer Walter a job and financial help, but he refuses out of pride.
After chemotherapy begins, Walter returns to cooking with Jesse and looks for a bulk buyer. Jesse approaches Tuco, Krazy-8's replacement as a wholesaler, but Tuco attacks Jesse and steals their meth. Walter retaliates by blowing up Tuco's hideout, then secures a supply deal with him. Tuco later kills one of his own men over a minor mistake, leaving Walter and Jesse wary of their customer. Hank's investigation traces a gas mask to Walter's school.