Spoilers ahead, you've been warned.
The tension with the cartel in Mexico has built up to this point, as the episode begins with Mike, Gus and Jessie getting picked up in a private plane and flown to Mexico. They meet up with Don Eladio and Jessie is there to cook a batch while the cartel documents his steps and keeps him as a peace offering. This damns Jessie to a life in Mexico as a cartel slave meth cook. However, Pollos Hermanos has other ideas about how it all goes down.
If you recall, 20 years prior (in a flashback), Gus and his partner, who started Pollos Hermanos, humbly visited Don Eladio, basically telling him they were going to sell on his turf. They offered him a deal. He responded to the deal by putting a bullet in Gus's partner's head and forcing Gus to watch his partner bleed out from 6 inches away. Uncle Tio was the gunman.
Gus and crew get sweet, sweet revenge by poisoning every halfway important cartel member at the pool party, Don Eladio included. This is shortly after Jessie spends a day talking smack to the cartel's stuck up chemistry professor cook and making a 96% pure batch of the Blue. During the cook, everyone present (must have been at least 50 people) had gas masks and cameras, and one was only a few feet from Jessie during the process. Although he was masked, I have a feeling this little bit of evidence will come back to bite him.
Meanwhile, in Arizona, Walt has some father/son time after finally crawling out of bed on his son's birthday. He's in a drug-induced haze, healing up from Jessie's epic beatdown, and says some things he wouldn't normally say. He openly cries and apologizes to his son. To his surprise, the next day, his son says he preferred the "weak" and honest version of his dad to the superman front Walt has been putting up for the last year. Oh, and Skyler buys him a Chrysler PT Loser for his 16th birthday and you can tell he really hates it after having the muscle car.
To keep her feet out of the fire, Skyler indirectly feeds Ted the money he needs to pay the IRS. What does Ted-tard do? Buys a brand new Mercedes SLK on lease and decides to open his business again. Stay out of jail, or resurrect the family business? It's a tough decision for him apparently. It's hard to understand that a guy willing to bang Walt's goofy wife would put the lives of his employees before his own. Are we supposed to believe that he has morals, but that his compass is skewed? Skyler visits him to put him in check, and he gives her a verbal tongue lashing before she lets him know that yeah, she's the one who gave him 600k to stay out of jail. Cliffhanger. *yawn*
Back to Mexico for the poisoning of the century. Basically everyone gets poisoned by drinking Gus's special tequila, including Gus, despite him taking some sort of antidote prior to the party. Mike puts on his badass hat and does some garrote work to Don Eladio's surviving bodyguard just as Gus comes back from the restroom. As they are leaving, Mike gets shot and Jessie empties an entire clip into the shooter. Gus gets dumped into the back seat of the car, Mike asks Jessie to "get us out of here, kid", and they all ride off into the sunset.
This episode really cements Jessie as an honest-to-god gangster. In an older episode, Gus and Mike set up a robbery to make Jessie feel better about himself. The trick appears to have worked very well, as Jessie is becoming powerful, hardened, and fearless. In his mind he has saved Mike's life twice now, even as Mike saved his in the last episode. He also delivered a serious ass-kicking to Walt last episode. Jessie has taken center stage, and the way the story is crafted, he deserves it despite his shortcomings (he's still not too bright).
The greatest part of this episode? No Hank. He isn't mentioned, they don't show his house, and his kleptomaniac wife doesn't stop by to chit chat with Skyler.
As Breaking Bad is wont to do near the end of the season, this one really turned up the heat. I had to watch it twice and will probably watch it again. Great stuff here and easily the best TV show ever.