Previously: Jesse and Mike decided to get out of the business before any more kids get killed (in Jesse's case) or the DEA catches them (in Mike's case). Walt took the news hard, particularly when they said they intended to sell their shares of the heisted methylamine for $5 mil apiece. That deal went sour, however, when the buyer demanded the whole kit and caboodle, so Mike chained Walter to a radiator and intended to sell the whole tank. Only he underestimated Walt's willingness to burn his wrist through MacGyver-y means, and so he returned to an empty garage. No methylamine, just Walt (with Jesse), saying he has a plan to get everyone what they want.
A great shot from the back of Mike's car shows us three bald heads in silhouette, driving out into the all-too-familiar Desert That Law Forgot, so I guess Mike believed Walt's (and Jesse's) claim to be able to deliver a scenario in which everybody wins. Walt pokes at his poor charred wrist, a succinct reminder of the lengths to which he went to bring about this scenario (or it would have been succinct if we hadn't just seen that very moment in the previouslies). Declan and his cronies are already assembled at the meeting spot, and before they get out of the car, Mike informs Walter that he's on his own, as far as presenting this deal goes.
Walt informs Declan that the methylamine isn't coming, and when Declan turns to Mike to find out what the hell is going on, Walt informs him that "you're dealing with me now." He tells Declan the methylamine is worth more in his hands than in anyone else's; what he needs is distribution. So here's the deal: Declan's organization gives up their cook to sell Walt's product, for a 35% share of the profits. Declan's all, "You're joking." Why would they want Walt? Walt is all too happy to describe how their product is 70% pure, if they're lucky, while his stuff is 99.1% pure, making this akin to "grade school t-ball vs. the New York Yankees" (oh, Walt, aren't the Yankees hated enough as it is?), or "tepid off-brand cola" vs. Classic Coke. Declan's like, okay, Steinbrenner, say I waste you right now, I guess there's no more Coke on the market. Walt: "Do you really want to live in a world without Coca-Cola?" He tosses a bag of the blue stuff on the ground and says he knows their outfit dyes their meth to look like his product; now they can sell "the real thing" (nice commitment to the metaphor there, guys).
Declan says no way he's gonna give up this deal, be Walt's "errand boys," just so some junkies can get a better high. Walt scoffs at the low-level thinking. That better high means the junkies will pay more. The purity of his product means a higher yield -- $130 million of profit that isn't being "pissed away by some substandard cook." Walts says they'd be getting the best meth cook in America, then stops and says the TWO best meth cooks in America (Jesse and Mike share a wary look at this), and with their skills, Declan earn more from that 35% than he ever would on his own. Declan's like, "Okay, why so generous then?" Walt explains that Mike is leaving (he doesn't mention Jesse), so they need a new distribution arm, plus a $5 million "finder's fee" for Mike. Again, no mention of a buyout for Jesse. Walt says he's got 40 pounds of product ready to ship -- "are you ready?" Declan picks up the bag of blue meth: "Who the hell are you?" Walt fixes him with a steely look. "You all know exactly who I am. Say my name." (Oh, Lord, Walt, these Scarface theatrics.) He continues, "I'm the cook. I'm the man who killed Gus Fring." Declan says that's bullshit -- the cartel got Fring. Declan looks to Mike, who shakes his head wearily. Walt, again: "Say my name." Declan finally does: "Heisenberg." Walt: "You're goddamn right."