Walter White, a New Mexico chemistry teacher, is diagnosed with Stage III cancer and given a prognosis of only two years left to live. He becomes filled with a sense of fearlessness and an unrelenting desire to secure his family's financial future at any cost as he enters the dangerous world of drugs and crime.
Gus tries to get Walt back in the business by offering him three million dollars and a brand new lab. Jesse is furious that Walt received half of the money for his blue meth. Hank tries to track down the RV meth lab.
Heisenberg's organized and practical assistant Gale greatly aids his work in Gus's lab. Hank finally tracks the RV back to Jesse, as a concerned Walt finds any way to erase the evidence.
Jesse ends up in the hospital after getting beaten up by Hank. Now he is threatening to press charges against the DEA. To stop him, Walt decides to bring Jesse on as his partner, once again.
Skyler hatches a plan as Hank's hospital bills stack up. Meanwhile, Walt and Gus come to a better understanding as Jesse, looking for more independence, pursues a new opportunity.
Skyler gets more involved in Walt's business, much to his chagrin, as Hank struggles with his recovery. Meanwhile, Jesse takes an active role in his new enterprise, leading him to a startling discovery.
Against Walt's advice, Jesse lashes out. Fearing for Jesse's safety, Walt takes drastic action to intervene. Meanwhile a tragic event leads to a shocking confrontation.
Jesse has disappeared and Walt is in big trouble with Gus. So Gus rehires Gale to learn from Walt's cooking so that they can dispose of Walt once and for all.