A man wearing nothing but tightie whities and a gas mask careens his Winnebago down a desolate highway in the New Mexico desert. In the passenger seat, another man-either passed out or passed beyond-also wears a gas mask, his head on the dashboard. Two bodies, even more likely dead, slide across the RV floor until the vehicle veers into a ditch. The hyperventilating driver, Walter White (Bryan Cranston), climbs out, dons the shirt still hanging off the side view mirror (his pants are long since gone), then re-enters the van to retrieve a video camera, his wallet, and a gun. He records a cryptic, handheld farewell to his wife and son. "I just want you to know that no matter how it may look, I only had you in my heart." That said, he faces the oncoming sirens, gun in hand.
Flashback to his birthday three weeks earlier. At dusk, Walt exercises on a mini-stairmaster in front of a plaque commemorating his contributions to some Nobel Prize worthy research. At breakfast, his happily henpecking wife Skyler (Anna Gunn) hands him a plate of eggs topped by veggie bacon spelling "50" before bantering with their handicapped son (RJ Mitte). Afterwards, Walt drops off Junior at the same local high school where he works as an ineffectual chemistry teacher.
Later that day, one of Walt's more disrespectful students witnesses him moonlighting at a car wash for additional income. The encounter is especially belittling since the student laughingly photographs his teacher wiping down the tires. A now publicly humiliated Walt returns home where Skyler has organized a surprise birthday party for him. Among the guests is Walt's gregarious brother-in-law, Hank, a DEA agent on the local news for busting a methamphetamine lab. Walt asks Hank (Dean Norris) how much money was recovered at the crime scene to which Hank replies "$700,000. Not a bad haul." Hank then invites Walt to accompany him on a bust. Meanwhile, in the kitchen, a woman fusses over Skyler's pregnancy and notes that she's "hardly even showing."
Another day at the car wash and the financially strapped Walt collapses and is taken away by ambulance. At the hospital, a doctor verifies the worst. The non-smoking Walter has inoperable lung cancer. Walt looks detached but he understands. "Best case scenario with chemo, I'll live maybe another couple years." Back home, Walt keeps the news from Skyler. At the carwash, he explodes when his boss asks him to wipe down cars again. Walter assaults the display racks. "Wipe down this!" he shouts grabbing his crotch.
And so the transformation of Walter White begins.
It continues as he joins his brother in-law at a drug bust. While the arrest is made inside, Walt waits in the car from which he spies ex-student Jesse Pinkman (Aaron Paul) escaping through a window. Later that night Walt stops by Jesse's house where he tells the baffled dealer that they can either partner or Walt will turn him in. "You know the business, I know chemistry," says Walt. An unlikely partnership is forged.
Walt goes to the school and steals beakers, flasks, and protective aprons. Jesse arranges to buy a used Winnebago so that their base can be mobile and harder to detect. The two drive out to the desert where Walt strips down to his skivvies, hangs his pants and shirt on the side view mirror, then gets to cooking the purest crystal Jesse's ever seen. "You're a damn artist," he says.
Jesse takes a sample to Krazy 8, a drug dealer who happens to be his former partner's cousin. Cousin Emilio, out on bail, believes Jesse ratted him out so the three drive out to the desert where Krazy 8 asks Walt if he wants to switch allegiances. Before he can answer, Emilio recognizes Walt from the police bust. Death threats ensue. Jesse tries to run, but trips and knocks himself out on a rock. Walt barters for his life by promising to reveal his cooking artistry so Emilio ties up Jesse and then goes to watch Walt work his magic. In the Winnebago, as Walt prepares the ingredients, Emilio throws a cigarette out the window, thereby starting a brush fire. Inside, Walt mixes chemicals that produce a deadly smoke before he dashes out. Bullets fly but Walt holds the door shut to seal these drug dealers' fates
Walt unties Jesse, puts a gasmask on him, and drops him in the passenger seat. We're back at the opening scene. With the sound of sirens closing in, Walt stands in the middle of the road then tries to shoot himself. To his dismay, the safety is on. His efforts to unlock it simply result in a pointless misfire. Suddenly, fire trucks, not police cars, appear. Walter stashes the gun in the back of his underwear. Jesse, sporting a black eye, comes out to join him. Walt's first day as a meth cook leaves him spent, shaken, but also invigorated. Back at home, he meets his wife's troubled queries with atypical sexual aggression which leaves her asking somewhat stunned: "Walter, is that you?"