Jesse Pinkman, Mike Ehrmantraut, and Gustavo Fring stand together out in the desert. After a long period of silence, the sound of a single-engine plane can be heard. It lands nearby and they board the plane. Jesse's anxiety during the Mexico-bound flight is palpable. "You can do this," Gus, who is holding a conspicuous giftbox, reassures him.
At the White Residence, it's Walter White Jr.'s sixteenth birthday. Unable to reach Walter White, Skyler White gives up and surprises Junior on her own with a sensible car parked in the driveway. Though underwhelmed, Walt Jr. politely thanks her, which quietly disappoints Skyler. It's clear Walt Jr. was not expecting a PT Cruiser.
In his office, Saul Goodman argues with himself. "This is a bad idea," he says, before paging for Ted Beneke to enter. Saul then struggles to inform Ted that his long-lost "Great-Aunt Birgit" from Luxembourg has left him $621,552.33—almost precisely the amount of his debt to the I.R.S. including fines. Ted insists he knows nothing of having a great-aunt, but on hearing the amount of inheritance is all too happy to ignore the details and keep schtum.
In Mexico, Jesse, Mike, and Gus sit blindfolded as Gaff and a leather-jacketed goon drive them to the Cartel's superlab. The chief chemist there takes an instant dislike to a 'too-young' Jesse, maligning him in Spanish as an amateur and a joke. When it becomes apparent that Jesse doesn't know how to synthesize phenylacetic acid, a basic ingredient that any chemistry student could easily synthesize, he becomes ever more indignant. Jesse senses that he's being disrespected and takes charge, telling Gus to "tell this asshole" if he wants to make a superior product, he has to do it Jesse's way. After the chemist responds in English, asking who Jesse thinks he is? Jesse responds that "I'm the guy that your boss brought here to teach you how to do your job", then calls the lab filthy and, channeling Walt, announces that no cook will take place until all contaminants are eliminated and every cook surface scrubbed ("Fly"). "So, stop whining like a little bitch, and do what I say," orders Jesse. They don't like it, but they know Jesse is right about their filthy lab, so they obey and start scrubbing. Both Gus and Mike can hardly contain the surprised pride from beaming forth on their mugs, so quietly impressed they are with Jesse's taking charge.
Walter Jr. drives in his birthday car to Walt's condo and rings the doorbell. Though inside, Walt doesn't respond until Walter, Jr. leaves a phone message threatening to call 911. Groggy, his face still battered from his fight with Jesse, Walt opens the door in his underwear and lets Walter Jr. in. After lying to his son by attributing his wounds to a fight that came out of his gambling addiction, Walt breaks down tearfully blubbering, "It's all my fault." Walter, Jr. comforts Walt and takes him back to bed. As Walt drifts back into sleep, he mistakenly calls Walt Jr. "Jesse."
At the Cartel superlab, workers observe and videotape Jesse as he begins the cook alone, lasting all night. Next morning the lead chemist analyzes the finished product in the gas chromatograph. After a tense few moments, the batch tests 96.2 percent pure and Jesse is ecstatic with relief. His product is not as pure as Walt's, though it is still superior to the cartel's. "First of many," congratulates Gaff. Jesse asks what he means. "You're staying," says Gaff. "You belong to the Cartel now," news which has shocked Jesse which he has yet to embrace.
Saul visits the car wash and shows Skyler a credit report indicating that Ted leased a Mercedes three hours after receiving Walt's money. He won't be able to pay the income tax bill in full—and clearly wasn't going to do so anyway.Walt wakes up late and sees that Walter, Jr. spent the night on the sofa. Apologizing for his behavior, Walt says that after he's dead, he doesn't want Walter, Jr. to remember him as he was the night before. He uses 'strong painkillers chased with beer' as cover for his sorry state. He tells Walt Jr. he wishes he could take it back, telling a story relating his own pity for his hospitalized father. Walt doesn't want his son to remember him like this, "like there was nothing in him." Walter, Jr. disagrees. Remembering his dad the way he was last night wouldn't be that bad. Unlike the past year, at least last night he insists "you were real." Once Walt Jr. leaves, Tyrus Kitt, who was parked nearby, pulls into Walt's driveway and asks Walt "Somewhere you should be?"
At Beneke Fabricators, Ted tells Skyler, who's dropped in for an explanation, that he's received a "very unexpected cash infusion" and is reopening the business. Skyler argues that he should use the money to pay his tax bill. When Ted responds that his inheritance is his to spend as he pleases, Skyler can't stand it, and blurts out that she was the one who gave him the money.
Back in Mexico at the Don Eladio's hacienda, Gus stands poolside on the exact spot where his partner Max was murdered years earlier. Calmly, Gus opens a small case and swallows one pill, which seems to have no immediate effect. Jesse complains to Mike about being abandoned in Mexico. Either they're all going home, or none of them are, Mike promises. Don Eladio Vuente appears with several capos, Gaff, and the lead chemist. "I'm so happy you finally came to your senses," says Don Eladio to Gus, referring to the Cartel's ultimatum. After a tense moment, Gus accepts Don Eladio's embrace. Gus introduces Don Eladio to Jesse—his new employee. The lead chemist mocks Jesse's training, but Don Eladio laughs. He taunts back that Jesse cooks superior meth and doesn't care about his training: "...with all your fancy college degrees." Don Eladio then spots the gift box Gus brought on the plane with him, which Gus offers "in honor of our renewed friendship." Delighted by the bottle of Zafiro Añejo premium tequila inside, Don Eladio has a waiter pour shots for everyone except Gaff and Mike. He then takes Jesse's shot back after Gus says that Jesse is an addict and needs to stay sober if he's to do his work. Poised for a toast, Don Eladio stops and warily eyes Gus, waiting for him to drink first. So Gus does drink first, as a show of good faith. After he drinks his shot, Don Eladio does as well, and everyone else follows suit.
"Enough business," declares Don Eladio, calling for a group of bikini-clad women to join the party. Sometime later, Don Eladio spots Gus sitting by himself and tells him he's not angry with him. He chides Gus for needing Don Eladio to "spank" him every twenty years, and that there's no room for emotion when it comes to business. Gus asks to use the bathroom. Still wary of Gus, Don Eladio has a capo escort him there. Once in the bathroom, Gus neatly lays down a towel in front of the toilet, kneels, and very calmly vomits; the pill he took earlier having been an emetic. Outside, Don Eladio involuntarily drops his cigar and becomes unsteady on his feet. One capo tumbles out of his chair and another loses his balance. Don Eladio's eyes narrow as he realizes they've been poisoned. Gaff moves to assist Don Eladio, but Mike slips in from behind and garrotes Gaff. Gus tidies up and leaves the bathroom, stepping over the corpse of his capo escort as he does. Outside, the stricken Don Eladio looks up and sees Gus, daggers in his eyes, he gasps, "This was you!?" before collapsing into the pool as he lunges for Gus. "Find a gun!" Mike shouts at a stunned Jesse, who pulls one off the nearest dead capo. Mike yanks Don Eladio's rather unique and trademark "evil eye" necklace off of his floating corpse.Gus begins to falter, vomiting again; the earlier vomiting in the bathroom having not happened soon enough. A crash then echoes inside the house. As Mike and Jesse draw their guns, Gus musters the strength to shout that Don Eladio and his capos are all dead. "You have no one left to fight for. Fill your pockets and leave in peace," Gus warns, "Or fight me and die." Unsure that this will prevent a shootout, Mike and Jesse both catch and prop up Gus and proceed through the house as the waiters and women scurry away with piles of cash in hand. In the driveway, Jesse finds a car with keys in it, and Mike eases Gus inside. Seconds later, Mike is shot in the stomach. Jesse wheels around and fires multiple rounds at Gaff's leather-jacketed thug, killing him. "Get us outta here kid," Mike says, with a tone of resignation, conscious that Jesse has just saved them all and now has total control over the stricken and unprotected Gus. Jesse jumps into the driver's seat and floors it out of the compound.
- The title "Salud" (pronounced [ saˈluð ]) is Spanish for "health" and is used as a toast ("¡Salud!").
- Most of the unidentified cartel gangsters killed in this episode are named in the next one, "Crawl Space". Of the 9 capos seen to have been poisoned by the poolside alongside Don Eladio Vuente himself and the cartel chemist Benicio Fuentes, 7 are named: Don Paco, Don Cesar, Don Renaldo, Don Artuno, Don Cisco, Don Luis, and Don Escalada. The lone thug gunned down by Jesse turns out to be Joaquin Salamanca, the grandson of Hector "Tio" Salamanca.
- The numeral "8" seems to appear conspicuously throughout this episode:
- The bruise on Jesse's face
- The airplane's tail number
- The clouds
- The Whites' house number
- This may be a reference to episode 8 of this season; "Hermanos", where there is a flashback of Gus' partner getting murdered directly in front of him. "Salud" ends with vengeance for this death being served.
- The licence plates of the cars at the end of the episode are from the state of Michoacán in México.
- In the scene where Gus forces himself to vomit, he turns on the tap. In the shot where he gets onto his knees though, the tap can be seen in the background with no water flowing from it.
- When Walt talks with Walt Jr. about his father, he mentions that he was tested for Huntington' s disease when we was a kid and resulted negative. This is not possible, as the disease was mapped in 1983 and the gene identified in 1993.
- In the pool scene where Gus poisons Don Eladio, Jesse is wearing the same leather jacket as Gus's former cook Maximus in the episode Hermanos when he is murdered.
- The lab instrument that supposedly displays the purity of Jesse's cook is actually a Gow-Mac gas chromatograph (the type of instrument referred to by Gale Boetticher in "Box Cutter"), but the readout shown is just a temperature display.
- This is the last episode that Mike sees Gus
- "He had Huntington's disease. It destroys portions of the brain, effects muscle control, and leads to dementia. It's just a nasty disease. It's genetic. Terrified my mother that I might have it, so they ran tests on me when I was a kid, but I came up clean. My father fell very ill when I was four, five. Spent a lot of time in the hospital. My, heh, my mother would tell me so many stories about my father. I mean, she would talk about him all the time. I knew about his personality, how he treated people, I even knew how he liked his steaks cooked; medium rare, just like you. I knew things about my father, I had a lot of information. It was because people would tell me these things. They would paint this picture of my father for me and I always pretended that was who I saw too, that I remembered. But it was all a lie. In truth, I only have one real actual memory of my father. It must have been right before he died. My mother would take me to the hospital to visit him. And I remember the smell in there. The chemicals. It was as if they used every single cleaning product they could find in a fifty mile radius, like they didn't want you smelling the sick people. There was this stench of Lysol and bleach, you could just feel it coating your lungs. Anyway, there lying on the bed is my father. And he's all... he's all twisted up. My mom, she puts me on her lap, she's sitting on the bed next to him so I can get a good look at him, but really he just scares me. And he's looking right at me, but I can't even be sure he knows who I am. And your grandmother is talking, trying to be cheerful as she does, but the only thing I could remember is him breathing. There was this...this rattling sound, like if you were shaking an empty spray paint can. Like there was nothing in him. Anyway, that is the only real memory that I have of my father. I don't want you to think of me the way I was last night. I don't want that to be the memory you have of me when I'm gone."
- ―Walt speaking to his son about his father.
- "Jesse in Mexico" by Dave Porter (as Jesse is taken to the cartel lab)
- "Bang Data" by Bang Data (during the party with the cartel)
- "Tidal Wave" by Thee Oh Sees (during the party with the cartel as the guests begin to pass out)
- "Salud" by Dave Porter (as Gus returns outside and they leave the hacienda)