
Jesse (left) vows to do Walt's dirty work again and kill Gus (right).

Jesse holds the capsule of poison that Walt gave him.
Walt hatches a plan to poison Gus with Jesse's help. Skyler now has a money problem of her own. Gus' meeting with the Cartel doesn't go well. Hank links Gus to Gale's murder.
Episode 4.07 - 'Problem Dog'
After disposing of the sports car (by setting it on fire), Walt visits Saul where he picks up some cash and asks Saul about getting a hit-man to take care of Gus. Saul says that anyone he could recommend Mike, Gus' henchman, would also know. When Walt says that he cannot even get close to Gus, Saul says that Jesse can. This gets Walt thinking. Meanwhile Walt takes the cash to the car wash.
Skyler does not know what to do with all the cash, it's too much for their car wash to be legitimately making. Walt tells her this is what she wanted, that he'd make the money and that she'd launder it. He asks her again if she wants out and takes her silence for a 'no.'
Back at the meth lab, Walt makes a poison and puts it in a capsule. He talks with Jesse and convinces him to kill Gus with it. The poison will kill after 36 hours. "I'll do it, I'll kill him [Gus] the first chance I get," Jesse.
Jesse got his first opportunity to poison Gus at the meeting with the Cartel. Mike told him to make coffee while they discussed business. However Jesse couldn't poison the coffee, Mike interrupted him before he could do it. Later Jesse went to his old 12-step group and told them he killed a dog for no good reason.
Hank makes a breakthrough in the Heisenberg case. He takes Walt Jr. to Los Pollos Hermanos, Gus' fried chicken restaurant. After Walt Jr. tells Hank about the sports car, Gus talks with them and gets Hank a refill of his soda. In the car Hank saves the cup in an evidence bag (hidden from Walt Jr.).
At the DEA office Hank lays out his evidence. He now thinks Gale was just a cook for the mysterious Heisenberg. A number on a Los Pollos Hermanos bag at Gale's place is a model number for an industrial air filter (suitable for a meth lab). It was made by a highly diversified German company. Gale signed for it but there's no money trail for the transaction. However the German manufacturer also owns Los Pollos Hermanos. Hank tells them he thinks Gus, who owns a number of Los Pollos Hermanos franchises, is involved in making meth. The others scoff and think he's nuts but then Hank reveals that he has evidence that Gus' fingerprints were found at Gale's apartment.

Gus greets Hank at his fried chicken restaurant.
Commentary and Analysis
It appears Gus' days are numbered. Who will get to him first? Walt and his poison through Jesse? Hank and the DEA? Or maybe the Cartel? However there's another alternative, perhaps Gus just decides to disappear. Like Saul suggested Walt do a few episodes ago. A war is brewing with the Cartel, a war Gus doesn't want to deal with so he just cashes out - takes his fortune and disappears for good.
And yes I think a drug war is in the offing. The two sides seemed too far apart for compromise. Gus wanted to make a one time payment of 50 million dollars to be done with them but that wasn't enough for the Cartel's representative. I'm guessing they want a piece of the action, an ongoing percentage of the ill-gotten profits. Finally it was very telling when Mike told Jesse he needs to learn to shoot, it may come in handy soon.
I still say Hank suspects Walt is involved. Why else would he hide the evidence bag from Walt Jr.? And Walt Jr. told him about the sports car, even though it was 'returned' it is suspicious. An unemployed high school teacher who won some money playing blackjack but who has a gambling problem spent his winnings buying a car wash and still has enough money left over to buy a fancy expensive sports car? Does problem gambling really pay that well?
Discussion Questions
- How will Skyler deal with all of the cash?
- Will Jesse try again to poison Gus?
- Why did Jesse tell the group that he killed a dog for no good reason?
- Does Gus really see loyalty in Jesse?