Season 1, Ep. 1 (‘Pilot’)
What Happens: After learning he has lung cancer and just a few years to live, Walt gets an interest in the meth business and enlists Jesse for his first cook. Things go sour, and Walt ends up killing Emilio and knocking out Krazy 8 after they threaten to kill him. Why it's the best: It clearly maps out the ingredients needed for Walt's journey from Mr. Chips to Scarface. The episode shows us the protagonist's ineffectual existence as Walter White and the first inklings of Heisenberg.