High school chemistry teacher Walter White is diagnosed with inoperable lung cancer and, desperate to secure money for his family, teams up with former student Jesse Pinkman to cook methamphetamine. The episode ends with Walt's first kills and the series' central moral line crossed.

Walt and Jesse must deal with the bodies from the desert -- one dissolves, one doesn't, and they're left with a living captive named Krazy-8 locked in Jesse's basement. Skyler starts noticing Walt is hiding something.

Left alone with captive Krazy-8 while Jesse detoxes, Walt agonizes over whether to release or kill him, ultimately strangling him with a bike lock after discovering he planned to attack. This is the episode that establishes Walt's capacity for murder.

Walt's former college friends at Gray Matter offer to pay his medical bills, but his pride forces him to refuse; this decision locks him into the meth path. Skyler stages a family intervention to pressure him into chemo, which he reluctantly accepts.

Walt, now in chemo, pushes Jesse to make contact with distributor Tuco; when Jesse is beaten and robbed, Walt takes matters into his own hands, walks into Tuco's headquarters, and blows it up with fulminate of mercury, demanding respect and payment. The 'say my name' moment before it was famous.

Walt and Jesse agree to cook a massive batch for Tuco, but need methylamine, leading them to rob a chemical warehouse. The deal goes through but Tuco's erratic violence makes him a dangerous partner, foreshadowing S2. Marie is caught shoplifting at the baby shower, a small but telling character beat.

After witnessing Tuco beat a man to death, Walt and Jesse quietly agree they need to eliminate him before he kills them. The first of the season's cold-open flash-forwards hints at a coming disaster.

Walt and Jesse are held captive at Tuco's hideout with his ailing uncle Hector. Hank stumbles onto the location, a shootout erupts, and Tuco is killed -- closing the season's first major arc in spectacular fashion.

Walt fakes a fugue state at a supermarket to explain his absence; Jesse is held for questioning. Both escape legal jeopardy for now, but 'Heisenberg' is on the DEA's radar for the first time.

When Badger is arrested in a DEA sting, Walt and Jesse hire sleazy attorney Saul Goodman to make it disappear. Saul immediately becomes an invaluable fixer and recurring series presence, reshaping how Walt operates.

A family party turns bitter when Walt and Hank clash. Walt's remission news should be a turning point, but he channels his restless aggression into home-improvement obsession, signaling the transformation into Heisenberg is now self-sustaining.

Saul brokers a meeting with Gustavo Fring, a fast-food manager with a vast distribution network -- the show's next major antagonist arrives. Jesse's disclosure to Jane triggers her relapse into heroin, setting the finale's tragedy in motion.

Holly White is born. Walt visits Jesse's apartment looking for his drug share and discovers Jesse and Jane unconscious and overdosing. He watches Jane choke to death rather than save her, calculating that she is pulling Jesse away from him. Devastating and irreversible.

Jesse spirals into addiction after Jane's death; Walt gets him into rehab. Jane's air-traffic-controller father, destroyed by grief, causes a midair collision over Albuquerque -- the disaster seeded in every season-two cold open. Walt's lie to Skyler triggers a formal separation.

Walt tries and fails to reconcile with Skyler, who now knows he cooks meth and files for separation. Two cartel assassins -- the Cousins -- cross the border and set their sights on Walt.

Walt breaks into the family home and refuses to leave, escalating the Skyler standoff. The Cousins arrive at Walt's house and are called off at the last second by Gus Fring, who has other plans for Walt.

Skyler tells Walt she slept with Ted Beneke to force the issue of separation. Hank has a panic attack in the field and is pulled from active duty, setting up his obsessive investigation arc.

Gus shows Walt a state-of-the-art underground meth lab and offers him $3 million for three months of cooking. Walt accepts, driving a permanent wedge between him and Jesse, who refuses to be cut out.

Hank tracks Walt and Jesse's old RV to a junkyard and nearly has them cornered. Walt and Jesse scramble to crush the RV in time, and a cruel ruse involving Hank's wife barely buys them the minutes they need.

Jesse realizes the drug crew he's supplying is using a child to carry out a murder. Skyler pushes deeper into Walt's business, and the confrontation with the street crew moves toward a breaking point.

Jesse plans to kill the dealers who used a kid as a weapon. Walt intervenes in the most violent way possible -- ramming them with his car and executing the survivor -- and then tells Jesse to run. A gut-punch pivot that sets up the finale.

Gus orders Walt killed and Gale positioned to take over the cook. Walt buys time by forcing Gus to keep him alive as the only one who can finish the batch, then directs Jesse to kill Gale before Mike can reach Jesse. Jesse pulls the trigger. Season ends on a gunshot.

In the aftermath of killing Gale, Walt and Jesse are held captive in the superlab while Gus decides their fate. Gus executes Victor with a box cutter in front of them -- a silent, brutal message that they are replaceable -- then lets them live and go back to work.

The cartel hijacks a Fring shipment as a show of force. Hank, now obsessed with the Heisenberg case from his wheelchair, shows Walt Gale's lab notes and W.W. dedication -- Walt deflects, but it's a near-miss. Walt and Skyler cover his gambling story at a family dinner.

Mike takes Jesse on errand runs -- ostensibly babysitting, but Jesse proves himself useful and Mike reports back favorably to Gus. Walt panics thinking Jesse has been killed, then is furious when Jesse returns fine and clearly being groomed.

Jesse delivers a harrowing, barely-coded confession about killing Gale at his NA meeting -- one of the show's most powerful monologues. Walt tries to poison Gus but can't get close enough. Hank presents his Gus Fring theory to DEA brass and is dismissed, but he's right.

Hank recruits Walt to help surveil Gus, unknowingly using the man he's hunting to spy on himself. The episode's centerpiece is a DEA interrogation of Gus where he's ice-cold, and a flashback reveals Gus's long, personal history with the cartel -- and why the Salamancas want him dead.

Walt discovers Jesse has been feeding intel to Gus, Jesse confronts Walt about sabotaging the cartel deal to protect himself. Their fight ends with Jesse beating Walt badly and ordering him out of the lab. The rift between them is now complete.

Gus fires Walt and threatens his family's lives if Walt interferes with Jesse. Walt rushes to Saul to arrange relocation for his family, only to discover Skyler gave their escape fund to Ted -- leaving him trapped. Walt's manic, hysterical laughter in the empty crawl space is the moment his world fully collapses.

Walt, trapped and desperate, builds a pipe bomb and waits for Gus at the hospital. Jesse is told that Brock (his girlfriend's son) has been poisoned, and he suspects Walt used ricin -- leading to a furious confrontation that Walt narrowly survives by suggesting Gus is responsible.

Walt manipulates Hector Salamanca into being a suicide bomber, killing Gus Fring in an assisted-living explosion. The famous final shot reveals Gus's half-destroyed face as he adjusts his tie before collapsing. Walt tells Jesse "I won" -- and the final scene reveals Walt poisoned Brock himself to turn Jesse against Gus.

Walt, Jesse, and Mike use a giant magnet to destroy Gus's laptop from the DEA evidence room. Walt asserts dominance over the new partnership, telling Skyler 'I forgive you' in a chilling power move.

The DEA traces Gus's operation to German conglomerate Madrigal; Lydia Rodarte-Quayle emerges as a new player. Walt strong-arms Mike into a three-way partnership and recruits him to cook with Jesse.

Walt, Jesse, and Mike set up rolling cook sites inside pest-control tented houses. Walt coldly reveals to Skyler that he watched Jane die, and cuts Victor's share from the business over her objections.

Mike and Jesse want to sell the methylamine and walk away; Walt refuses because the cook is his identity. Jesse ultimately stays, and Mike cuts his own deal. Walt's 'empire business' monologue makes his transformation explicit.

Walt brokers a deal with Declan by forcing him to say 'Heisenberg,' cementing his dominance over the Southwest trade. Mike tries to leave but Walt kills him over a list of names -- a senseless, rage-fueled murder.

Walt reaches the peak of his empire -- a time-lapse montage of money and product -- then abruptly retires after a cancer scare. The half-season ends with Hank finding Walt Whitman's 'Leaves of Grass' in the bathroom and realizing Walter White is Heisenberg.

One year later, Hank confronts Walt directly and demands he turn himself in. Walt refuses, warns Hank off with a thinly veiled threat, and Jesse -- drowning in guilt -- starts burning his drug money in the streets.

Walt buries $80 million in barrels in the Tohajiilee desert and memorizes the GPS coordinates. Hank pulls Skyler aside hoping she'll cooperate; she refuses -- but her commitment to Walt is clearly crumbling.

Walt secretly records a fake confession that frames Hank as the drug kingpin -- a masterstroke that leaves Hank with no play. Jesse realizes Walt poisoned Brock and stole the ricin cigarette, and goes full feral, ready to burn Walt's house down.

Hank and Gomez convince a suicidal Jesse to become an informant and wear a wire. Jesse devises a scheme to hit Walt where it actually hurts -- threatening the buried money -- and Walt takes the bait.

Jesse leads Walt to the Tohajiilee desert where Hank and Gomez arrest him. Walt calls Jack's neo-Nazi crew for backup, then desperately tries to call them off -- too late. The episode ends mid-gunfight on a cliffhanger.

Hank is executed by Jack; Walt's fortune is taken; he tries to give up Jesse and watches him get dragged away. Walt kidnaps Holly, poisons Skyler over the phone to give her DEA cover, and leaves Albuquerque alone. The White family is completely obliterated.

Walt hides in a frozen New Hampshire cabin, alone and dying. Jesse is kept as Jack's meth-cooking slave. Walt nearly surrenders to the DEA but spots a Charlie Rose interview with Gray Matter's founders, reigniting his pride -- and he disappears into the night.

Walt retrieves his money, poisons Lydia with ricin, says goodbye to Skyler, and builds an automated machine-gun contraption that slaughters Jack's compound. Jesse kills Todd and escapes. Walt dies alone on the meth lab floor -- finally, genuinely content.