Contains spoilers for this episode and earlier episodes.
Jesse is in hiding after the deaths of Gus's street dealers, while Walt tries to negotiate a return to work. Gus permits it but chooses the replacement partner himself: Gale comes back to the laboratory under Victor's close supervision. Gus encourages Gale to learn Walt's method, presenting Walt's cancer as a reason to prepare for his absence. Walt concludes that once Gale can reproduce the product independently, neither he nor Jesse will be needed. Saul misdirects Mike's search for Jesse, allowing the partners to meet privately and discuss their options without revealing Jesse's hiding place.
Jesse urges Walt to go to the authorities, but Walt refuses. They instead plan to kill Gale so Gus will still need Walt to run the lab. Jesse cannot accept carrying out the murder, so Walt agrees to do it himself after Jesse finds the address. Before Walt can leave, Victor takes him to the laundromat on the pretext of a chemical leak. Mike is waiting, and Walt realises that his time has run out. He offers to surrender Jesse, using the promised telephone call to tell Jesse to kill Gale immediately. Victor races to intervene while Mike tries to warn Gale. Jesse reaches the apartment first, raises his gun at a pleading Gale and pulls the trigger. The season ends on the shot.