
Jesse, Mike, Walt and Gus (l. to r.) at the lab in the first episode of season four.
The fourth season of Breaking Bad picked up right where season three ended. Walt had Jesse kill Gale because Gus was going to kill them and have Gale take their place cooking meth. Walt, the formerly mild-mannered high school science teacher with terminal cancer, is now deeply immersed in the world of illegal drugs. How will he deal with it?

Gale, he also knows how to cook meth.
Episode 4.01 - 'Box Cutter'
The episode opens with a flashback of Gus and Gale. Gale is telling Gus that he needs better equipment to produce a higher quality of meth. Gus informs gale that he will no longer be needing his services, he has someone else who can produce high quality meth without the extra equipment. That someone is Walter White.
Back in present time, we see that Jesse actually went through with it and killed Gale at his apartment with one shot to the face. Maybe if Gale wasn't such a nice guy and was a bit ruthless then he would have killed Walt?
Mike, Gus' henchman, takes Walt back to the secret meth lab. Jesse is there too. Mike keeps them seated as Victor begins to cook a batch of meth. Maybe Gus doesn't need Walt after-all? The tension builds as Gus arrives and silently changes into lab work clothes.
Walt senses what's going on and pleads his case. Just what does Victor know about chemistry? Making meth is complicated, there are many steps. Quality requires attention to detail. Victor responds that it's called a 'cook' for a reason, you just have to follow a simple recipe.
What is Gus' reaction to this? He takes a box cutter and kills Victor by slitting his throat. Walt's job is safe - for now anyway. Walt worries that as soon as he can Gus will kill him.
Elsewhere in the episode, Skyler is worried about Walt. She visits Saul and then Walt's place looking for information. She doesn't find much. Meanwhile Hank, Walt's brother-in-law who's a DEA agent, is still recovering from being shot. He is also concerned about minerals.
The show ends with police and CSIs at Gale's apartment.
Episode 4.02 - 'Thirty-Eight Snub'

Walt with his new little friend.
Walt is buying a gun. Is it for personal defense or does he have something else in mind?
Here's a clue: Walt is buying the gun on the black market and it has the serial number filed off of it. Also the guy he's buying it from wonders why he doesn't just buy a legal handgun if it is truly for self-defense. Walt quietly asserts that it is for self-defense as he handles the snub-nosed revolver (it's a Ruger LCR according to the IMFDB) .
Walt's intention becomes clear as he approaches Gus' house late at night. Mike calls him on the phone and tells him to go home, he's being watched all the time. Next Walt takes the gun to the lab and is disappointed when Gus doesn't arrive. Tyrus comes to lab instead, he's Victor's replacement. Walt wants to see Gus in order to "clear the air." Mike tells him that he will never see Gus again. That Gus sounds like a smart guy.
Next we see Walt in a bar talking with Mike. Walt says that they're "in the same boat." Mike can't feel safe around Gus, can he? "Just get me in a room alone with him [Gus] and I'll take care of the rest," pleads Walt. Mike responds by beating Walt up. He punches him in the face and kicks him when he's down. Walt has his answer. Mike seems very loyal to Gus.
Meanwhile Jesse is partying with friends. Andrea shows up and wonders why he gave her all that cash (her brother was killed in drug-related violence). Jesse assures her that the money has no strings attached and she should use it to get her kid away from the drug violence.
Skyler tries to buy the car wash to use to launder money but the owner doesn't have fond memories of Walt. Hank is obsessed with minerals, he's bought a lot of them for some reason.
The episode ends strangely. The party at Jesse's has ended and he's alone. He plays music and then leans back into a big speaker.
Discussion Questions
1. What will Walt do next? Continue to try to kill Gus? Keep trying to win Mike over? Start playing defense? Find a way to make himself irreplaceable?
2. What will Hank do with those rocks? I mean minerals. Were the minerals in a previous season?
3. Why isn't Jesse as worried as Walt?