I mean, there was no way the recaplet of the finale wasn't going to start with a holy shit so let's get that out of the way: HOLY SHIT.
Let's also get this out of the way: mea culpa to everyone who called that Walter really did poison Brock. Even though it wasn't exactly like y'all thought, and even though I certainly never maintained that it was something Walt wouldn't do. The bastard.
Anyway, so what happened: in the aftermath of the car non-bomb, Jesse gets picked up by the Feds for questioning about his ricin claim re: Brock. This keeps him out of the way while Walt bull-in-a-china-shops his way to find Saul. He needs to find another venue where he can get to Gus, and after talking to Jesse, Saul gives Walt one possibility: Tio Salamanca. After ascertaining that Tio and Gus are enemies, Walt pays the old man a visit and gives him an opportunity for revenge.
The plan goes like this: Tio makes a request to see the DEA. Hank schleps in for the occasion only to get some slowly spelled out epithets tossed his way by Tio, but the point is that Gus hears about it. Tio's gotta go. So while Walt hides out in at the old folks' home, Gus sends Tyrus to scout Tio's room and make sure the coast is clear for Gus to show up and give the old bastard a lethal injection. Only Tio gets the last laugh, as he rings his little bell that's been rigged up to Walt's bomb. Tio's room goes BOOM, and Gus emerges ... with the entire right side of his head blown off. Rest in peace, sweet chicken man.
Meanwhile, Jesse is freed from custody when it's found that Brock wasn't poisoned by ricin after all. But Jesse's not free two minutes before he's picked up by Gus's men and forcibly taken to the lab to cook the next batch at gunpoint. After hearing that the explosion at the old folks home went according to plan, Walt shoots his way into the lab, liberates Jesse, and the two of them burn the mother down. When they convene for a post-mortem, Jesse relays the news that Brock is on the mend, and that it wasn't ricin poisoning but ingestion of lily of the valley. Walt is relieved the kid is okay, and he assures Jesse that even though this means Gus didn't poison him, he still had to go. Jesse, damaged and tortured as ever, reluctantly agrees.
After Jesse's gone, Walt gets a call from Skyler, who's been watching the news reports about the bombing and the laundry fire. That wasn't Walt's doing was it?? She asks him what happened. Walt: "I won." Cut to the Whites' backyard and the potted plant next to the chair where Walt was spinning his gun last week. That potted plant? Lily of the valley.
So the car bomb didn't work. That's a bummer. Walt races to the parking garage to recover the device -- being awfully careless in throwing around the bag (which ... is that a diaper bag?) that carries the trigger to the bomb. Into the hospital he goes, to tell Jesse/accuse him of tipping Gus off. Jesse is all WTF about bringing a BOMB into the hospital, and both men start growling insanely at each other. Walt needs to know where else they could possibly get to Gus that isn't completely covered with cameras. Walt's like, give me ONE place! But Jesse can't think of any place -- or any thing, really. He's shaking with panic. They're suddenly approached by two besuited men -- ABQ police. They need to ask him questions about Brock. Walt tries to interject and throw his weight around, until the cops are like, "And who are you?" and he remembers that it's probably best not to stick his neck out with the POLICE. The cops walk Jesse away, and everybody gulps at the implications.
After the credits, Jesse's in an interrogation room. Why'd he tell Brock's mom that he was poisoned? Jesse downplays it, says he was just trying to help the doctors cover all bases. He was awfully specific, though. Ricin? They threaten that the FBI could come down on him next. They're all sarcastic with him about how helpful he was being, suggesting ricin. Congrats, the doctors think he might be right. Jesse tries to explain it away as something he saw on House or something. And more importantly, he wants to see his lawyer. The cops make their usual "Oh, you don't want to do that!" spiel about lawyers. They always complicate things! This isn't Jesse's first rodeo, though. He repeats: "Saul Goodman. Get him."
At Saul's office, his poor, put-upon secretary, who I'm not sure has been named so let's just call her Flo, is shredding documents. She's also ignoring phone, and then ignoring the knocks at the door, even as they become louder and more urgent. Suddenly, there's a crash of broken glass. She grabs her pepper spray and watches Walt climb through the blinds and broken glass like an ogre. She's all WTF are you doing here? He needs to see Saul, who is not there. She's like, "Oh what else is new?!" She's so pissed at him, you guys. "Let me explain something to you," Walt condescends. "My partner and I..." Flo: "...are in DANGER??" She's like, "Whoop-tee-fricking-doo!" Walt and Jesse are in danger again? After doing something idiotic? "You are such a pain in my ass," she says. She's gotta go on unemployment for God knows how long, and now she can't even get out of here until she gets a guy to fix the door. "Who pays for this?!" she demands. Walt pulls out $1,700 and "apologizes" for the door. Flo gets opportunistic, though -- and good for her! -- and says the door's going to run more like $20,000. It takes Walt a while to get what she's talking about. Shakedown! She bumps it up to $25,000, and Walt snarls at her. He crawls back out of the door to go get the money.